How to combine IF & OR Functions

[Marcie Be]

I have the following IF Formula in cell AJ20 = =IF(AT20<>"",AT20+1,IF($C19="Fast Track (CR)",$S20+1,IF($C19="Cost Only",$AJ19+5,IF($C19="Data Transfer","")))) Which produces a FALSE. I think becuase Cell AT20 is empty no data yet added. Once I enter a date into cell AT20 ceLL AJ20 returns the date + a day which is what I want.
Before I enter a date into AT20 I want AJ20 to be empty/blank
The following formula gives me that
Cell AJ =IF(OR(AT20<>""),AT20+1,"")

Because of othe requirements I have had to use the longer formula for AJ20 shown above. I need to combine the two. Advise on how to do this please is requested.

Thank you in advance

Regards

Marcie Be

 

[AlanY]

how about

=IF(AT20="","",AT20+1,IF($C19="Fast Track (CR)",$S20+1,IF($C19="Cost Only",$AJ19+5,IF($C19="Data Transfer",""))))

 

[Marcie Be]

how about

=IF(AT20="","",AT20+1,IF($C19="Fast Track (CR)",$S20+1,IF($C19="Cost Only",$AJ19+5,IF($C19="Data Transfer",""))))

Thank you @AlanY
Unfortunately it does not work, says I have too manyy arguments.
I am trying to figure out why