Issue with Google Daily Budgets

I have researched this question and cannot find an answer.

I manage several accounts where it is important to my clients that the allocated monthly budgets are spent. Where many are concerned that the monthly budget is exceeded, my issue is that at the end of the calendar month, my clients want the monthly spend to very closely match the allotted budget.

My issue is that the monthly spend is below the allocated monthly budgets. Setting the daily budget using the monthly budget divided by the average days in a month of 30.4 fails when the Ads are not scheduled 7 days a week. I have many accounts where the Ads are only running 4-6 days a week. This is causing the monthly spend to fall below the allotted budget.

Towards the end of the month, I'm having to nurse the daily budgets on multiple accounts every day in order hit the allocated budget goals. This is very time consuming and inefficient. Simply raising the daily budget above the formula amount is a guessing game.

Does anyone have any suggestions on how to address this issue in an effective and efficient manner?

Thank you in advance.