pct start 2 0r 3 weeks?

just finished my second cycle of test/deca/d-bol. My first cycle i started pct 2 weeks after the last shot. On the cycle chart is says to do it 2 weeks but I hear from others on this site to do it 21 days after. Does anyone know and why do you have to wait a couple of weeks? Thanks

test sus at 500 weekly

when did you finish the deca?was it the same time as the test or 1 week earlier like it should have?pct start time for sustanon is 18 days and for deca it is 21 days.

I took the test one week longer. Is there a reason to wait 18 days?