Premom HPT

Does anyone use Premom test strips? I got a positive on the hpt 11 dpo. Now I’m 16 dpo and the line is still faint. There, but faint. So I got a free and it popped up strong immediately. I was just looking for line progression, and not getting it. But the frer is so much darker. So wondering if the premoms are just more faint in general?