Figuring out compensation for all the behind-the-scenes work: Any input?

Yes, you should be compensated for your time!

"I have been using a spreadsheet to track my hours and over the past 6 months I have a minimum of 150 hours which didn't count a lot of things like attending care meetings, personal care errands, travel times, shopping for her personal needs, etc. "

Keep track of ALL of your time, not just the bookkeeping tasks!

My mother likewise would have never qualified for Medicaid. I was compensated $20/hour, and this didn't include any bookkeeping. No taxes were taken out; it was gifted per IRS rules. Even your MIL wants to pay you! My mother got angry when I brought it up to her ("You don't pay family!"), but when she declined suddenly and severely upon hospitalization (and never recovered), one of the POA brothers agreed to compensate me (including back-pay!). Good for you for at least keeping track of all the bookkeeping work you did/do!

Bill MIL $30/hour for the financial work. If she wants to pay you for doctor's appointments and such, then I might charge about 3/4 of that amount.

I paid myself (as Trustee) $20/hour for my work the first year I took over my mom's finances, because it really did take a ton of time. Eventually, though, it sort took care of itself with automatic bill paying and such, so I stopped charging for it. I have been using the trust to pay for my gas lately as I've had to go back and forth a lot lately as I prepare my folks' house for sale. I'm going through two tanks a week, and that's getting a little too rich for my blood. Seems only fair to let my brother pay half of it now that my folks are both gone and we've inherited the money. He doesn't do much of the actual work, so he can do his part by paying a fair share of getting me there from 40 miles away.

A Licensed Fiduciary would cost approximately 90.00 an hour no matter what he was doing, including paying all bills, keeping meticulous financial records and etc. As you are DIL I think that hourly cost is too high, but I don't think 30.00 is out of line. It should not be hard with your experience for you to keep track of time in all this; it wasn't hard for me as POA for my brother, and I didn't charge at all (but was aware of the time expenditure). Diaries and record spread sheets account for your time and what it was for. Supportive care and your accounting work? The division will be clear as you do the work; it sure was for me.
Best of luck. Whatever you charge should be clear, and you will need W2s for your work and to claim this money on your taxes; I feel you should run it by a financial elder law attorney, possibly write out simple contract so that this can never be called into question by any relative or any entity such as the state should state assistance ever be required by your elder. Laws are very particular about prevention of self enrichment for POA and family; sometimes court permission is needed for you to serve in this capacity (up to your state's rules and guidelines)--so pass this past an attorney, not a forum.
Wishing you the best.

First, kudos to you for doing yeoman's work out of the goodness of your heart. Been there, done that with my MIL and SFIL while I worked FT and had 3 kids in school.

It's very important that you understand this is a global forum and laws that pertain to what you are asking are often local, so beware of taking advice here from anonymous participants where there is no accountability.

Family members getting paid for "caregiving" is a sticky area for many reasons. One is that MIL's Medicaid qualification must be protected -- unless she is very well off financially. Any "payment" to a close family member can be interpreted as "gifting", which has a low bar and Medicaid gets to decide what's gifting and what's not. In most states (Medicaid is run independently by each state) the application "look-back" period is 5 years.

https://www.agingcare.com/articles/how-to-get-paid-for-being-a-caregiver-135476.htm

Is there a trust? I live in MN and we just complete a Living Trust. In it, the trustees can be compensated for their efforts that are directly related to managing the trust and for caregiving. You aren't a trustee, so your husband should read the document to see if this is made possible for him. Then *maybe* a workaround is that he "hires" you and pays you (and you submit a detailed invoice). This may not fly with any other family members. Personally, I would consult with an experienced elder law attorney/estate planner to get the correct legal answer to this question. Don't do anything until you know for sure. You will also need to know what the average going rate would be for similar services you render.

It might be a better solution to just outsource what is outsourcable and let the family come to the conclusion that paying you (if legally possible) is a more desireable option. A combo of bookkeeper and geriatric manager. What you would charge for and not charge for may also be a question for the attorney and be prepared to have solid answers for when the other heirs (and heaven forbid, Medicaid) look upon this arrangement as "enrichment".

Get all the facts first before presenting your desire to the other heirs. It may be a no-go legally and then you'd need to figure out whether you're burnt out and would like to hand-off or retire from this responsibility, which would not make you a bad or selfish person in any way.

Can you clarify if your MIL is deceased or still alive? The reason I ask is that your post refers to "estate" and "heirs" but also that your husband and brother in law have POA and that your husband and MIL feel you should be compensated for at least some of what you are doing. Assuming your MIL is alive, it's difficult to sort out, as you say, which tasks might be compensated and which not. If you are not the POA, I'm wondering how you handle all the financial records, bill paying, etc.? Presumably you are doing this to help your husband in his POA role, and he would be the one legally responsible. If it were me, I might consider compensation for the financial management side of things, but perhaps not for the coordination with NH, doctor's visits, etc. Your MIL's funds should be managed with her best interests in mind, not in the interests of preserving the estate for her heirs. If she and your POA husband are in agreement about your receiving some compensation, they should make sure the other POA is an agreement and that there is openness and transparency. There should be no possible suggestion that thre is "self enrichment" going on, given that you are the spouse of one of the people with POA. I well understand your resentment that you are shouldering an unfair burden in handling your MIL's affairs. Unfortunately, if you're good at something (e.g., financial and organizational skills) and someone else is not, it's all too easy for the burden to fall on the more skilled person.

Look up what it costs to hire a Geriatric Care Manager and a CPA.
Geriatric Care Manager about $50,000 per year that goes up to $100,000
CPA maybe about $30.00 per hour
How to track your time, just as you would if you were working for someone else. Log the time you start a project and when you finish it. If you take a break for a length of time "clock out" but if it is a break for lunch or just a bit of time time to toss a load of clothes in the drier I would not bother to "clock out".
You deserve to get paid for the time you are putting in.