If it makes you feel better, then keep doing it bro. Different things for different people. I need to stretch more myself lol. 2 hours though? Jeez I would get bored fast. If you ever get a crazy shoulder pump that affects your workout, do like the other guys said and hang from the bar, works like a charm.

Loaded static stretches can induce hyperplasia...
As I understand it, you need to isolate the muscle...

Be careful bro...
Many gymnasts snap bicep tendons from moves like the back lever... I doubt you're doing those moves, just word of caution.

Therapy-wise.... ART is based on this. It heals adhesions and is a tool everyone should have in the form os therapy, self therapy and voodoo floss bands.

Training-wise.... If you want to know if stretching fascia gives gainz on not (it really does and is scietifically proven you know), then try bloodflow restriction training with intraset stretching

e.g. BFR applied above biceps. 30-40% normal working weight (be prepared to lower it). 4 sets 30 reps fast but controlled, focus on hitting near to max contraction and then max stretch as fast as possible
half second reps say, as long as is controlled
Then stretch out the bicep, contract the tricep to achieve max bicep lengthening, for 30 seconds
then straight back to set 2
do this 4 times and do 2 stretches at the end. once with the straps on, once when you remove them (remove after say 2 mins from end of last set and stretch again, min 30 secs all stretches
(you may need hooks! you may cry)
if you want to get hardcore
do tricpes and biceps together. using say a light short barbell.
rotate from bicep to tricep and do 2 sets (with then without BFR straps at the end)
(you may cry)
The stretches must be weighted, so the lighter bar or dumbells are already ideal for it.
a good combo is barbell curl or spider curl into skullcrushers

you will experience new growth with BFR + intraset stretching

You will not gain more through stretching but its very good against injurys and helps u to keep your muscles and tendons stable respectively stretched.
I do it once a week 30-45 min