Nested Formula help

[Pat Flynn]

I am trying to setup a spreadsheet that will track invoice billing. Time
period starts at drop date. If mtdate is completed, then mt-drop. If mtdate
is "", then 1st period invoice-drop date.
My problem is the billing periods. Can't get formula to work so that it
adjusts for mt date and billing period.
I would like the billing periods to trigger the invoice amounts for each
billing period. Thanks for any suggestion to set this up correctly.
Pat

Drop Date
MT Date
Free Day
Tot Billable Days
Tot Detention Billed





1st Period Invoice
=IF(AND(MtDate="",B29=""),(A1*((TODAY()-B9)-FreeDays)),(IF(B29>MtDate,((B29-B9)-FreeDays),"help")))
2nd Period Invoice
3rd Period Invoice
4th Period Invoice
5th Period Invoice
6th Period Invoice
7th Period Invoice
8th Period Invoice


1st Billing Period
2nd Billing Period
3rd Billing Period
4th Billing Period
5th Billing Period
6th Billing Period
7th Billing Period
8th Billing Period