Nested IF statements in Excel, or maybe another formula
Solution 1:
You put your two IFs inside an outer third one like this (assuming Dispatcher is in column D, for example):
=IF($D4="Alan",IF(P4>(T4+18000),"A",""),IF(P4>(T4+20000),"A",""))
being slightly more sly, you could put the dispatcher "switch" in the middle of the other one:
=IF(P4>(T4+(IF($D4="Alan",18000,20000)),"A","")
or even use the comparison as a simple true/false statement which Excel will treat as 1/0 as soon as you do maths on it:
=IF(P4>(T4+20000-2000*($D4="Alan")),"A","")