Hi @Wooloomooloo2 ,
I have run into the same issue that you mention and have done a similar comparison with Personal Capital, with the same result. What I ended up doing is set the Withdrawal Rate to zero and let the negative cash flow rate basically dictate the withdrawal amount.
Any additional income events I have recorded on the Cash Flow worksheet with applicable date ranges. This seems to work good for me, hope it helps you as well.
Note: it appears that when you specify a Withdrawal Rate, that amount is considered separate from the Cash Flow Forecast value and is considered as spent money.