Yes, There is a problem with volume with all the scripts, and when backfill is pressed the volume bars which are minuscule or missing gets updated and amplified. BUT this is the problem with almost all of these vendors . I tried 3-4 of them in the past one week and almost all of them have issues with Volume charts.
Now another question comes to is reliability, can we rely on these feeds? I think Josh/Tracerbullet utility is far more trustworthy and reliable, moreover codes could be tweaked if one is capable of. Regards