2015 Prescident Speed Code 4 is a Dud

[jason78]

As mentioned on several other threads, I have just purchased a 2015 Prescident. At full charge, I can get it up to about 15 or so via GPS on a flat surface. Figured it was set to the normal Speed Code 3. Took it to the CC Dealer today to have SC4 added just to find out it already has speed code 4 and he ran through everything with the tool and could not find any other issues. He didn't really have any thoughts as to why it would not get closer to 20. Going down a hill I can easily get it to 20 but still tops out at 15 on flat surface. Saw 16 a couple times after a sustained 15. Running stock 18x18.50 tires

Is there something I'm missing here? I really don't have a desire to go over 20 but was really wanting to at least get it there. Based on other threads it sound likes I'm not the first to see this happen but it also sounds like plenty of people are getting every bit of 20 with SC4. What could I be missing? Thanks!