Darker mean more hcg?

On our third cycle of Medicated timed intercourse with Letrozole.

Got my bfp faint line 9Dpo and have been testing to see if line gets darker.

Is it true that the darker the line the more hcg???

Went in on 11dpo and my hcg was only 15 but progesterone was 26. Lines are getting way darker. Go in for second blood draw today.