You should be measuring BPEL for tracking gains. NBPEL is unreliable. You may have already produced gains but not been able to tell due to your measuring method.
Are you doing 10 repetitions of each stretch direction? If so, that is quite a bit so I cannot recommend more there. I do think that you could stretch more often if you monitor your fatigue level. I think stretching Monday through Friday and taking the weekend off is a reasonable place to start.
Do a 20 second “piss-pull” after urinating to keep it from turtling throughout the day.