I always lift a bit lighter after STS and think I still keep my results. The key is to keep pushing yourself, even with much lighter weights than you lifted in STS.
I find that even with something like the pyramids, for example, I lift heavier than I did before to keep up the same intensity. So whereas before STS I might have matched the girls on weights, now I will lift heavier. So for chest I might have done 12, 15, 20 before and now I will do 15, 20, 25 or even 20, 25, 30 with a longer rest between sets. Or where I might have used 5# for rear delt flys for a high rep set, now I'll use 8 (where in STS I might use 12).