Adjusting W-4 with a fluctuating income

Question: Can I put 99 allowances on my w-4 and then put a set amount to be withheld if I know my estimated tax liability for the year?

So I have a job that gives me a weekly paycheck, I also receive 2 lump commission/bonus checks this year. I know the maxium amount for these bonuses (though I could miss my target and not get the whole amount). I have already received one bonus and had a large chunk taken out for Federal taxes. By my calculation I have already paid the federal government more than 50% of my 2016 federal tax liability to this point and I'm only 8 weeks into the year!

Instead of changing my w-4 multiple times this year for when/if I get my commision checks, could I instead put 99 allowances down on the w-4 and then also request that they deduct a set amount from each paycheck? It's much easier to calculate that for the next 44 weeks, they should withhold $150 from each check instead of fiddling with a withholding calculator.