Well, if you think about it, going from L-S GPP to S-L later means;
Long -> kind of short -> back to long again
So what you might be losing is acceleration development. If so, your performance above 60 in the 80-150 range later might be off because MaxV is off, because you aren’t doing enough accel development early to reach a high enough MaxV. The Jamaican programs are using plenty of work in the 300-450 range for GPP, but also plenty of power development in that same GPP using sleds and hills. If I was starting L and planning to go S-L later, I would be incorporating some S work in GPP in the 30-50m accel range.