We are running Time Slips 2019

The end result that I am wanting is this:

I want to be able to put the amount of the initial retainer in the system. for example lets say retainer is $2900.00 but the client only pays $1500.00 of that retainer. I want the bill once printed to show they still owe $1400.00 on retainer. But at the same time I would like to be able to see time slips total. so lets say our slips total is $3700.00, with this being said that $700 would come off of the retainer portion that has been paid $1500.00 which means they not only owe me $1400.00 on retainer they also owe  I want the bill to show that they client total still due is $1400.00 for remaining retainer plus the $2200.00 (diff of 3700.00 and 1500.00)

I have tried funds to account, i have tried regular payments and above