Not a cardiologist but Praluent has the following indication in the USA:
PRALUENT is...indicated as adjunct to diet and maximally tolerated statin therapy for the treatment of adults with heterozygous familial hypercholesterolemia or clinical atherosclerotic cardiovascular disease, who require additional lowering of LDL-cholesterol (LDL-C).
Oddly, no mention of HoFH. But both are approved for ASCVD.
It's up to the company, Amgen, to make the announcement, not the FDA. Amgen will do whatever seems most appropriate to them. All companies handle things their own way and those ways can vary over time.