I believe there is a difference between credit weight and gpa weighting. I am looking at my kids’ old transcripts and their AP courses were all 1 credit. However, there was a separate legend for each AP and other weighted courses that indicated that 90-100 =5.0, 80-89 =4.0, etc… or in other cases 90-100 =4.5, 80-89=3.5, etc…
If credits were used as the gpa weighting factor, the max weighted gpa would still be a 4.0. This kind of credit weighting would help a kid who made say an A in a 1.5 class and say a B in a 1.0 class (wgpa = 3.6) and would actually hurt a kid that made a B in a 1.5 class and an A in a 1.0 class (wgpa =3.4). In a traditional weighted gpa system (all classes 1 credit), both kids would have a wgpa of 4.0.