So far, not one person has defended my basic premise, which is this- if you're horizontal, use your rear dumps. If your vertical, use your hose, and if pulling the velcro tab hose router helps empty the bladder, then do it! I guess I must be wrong.
Vertical use the shoulder dump or if fitted pull hose dump. OR just go horizontal and use the lower dump and yes this does work on the surface.
Pulling the velcro is not how to do it. IF the bcd fits properly it should be so high as to fit on the top of the shoulder so not benefit from going higher.Also runs the risk of losing it, getting tangled behind and so on. Its there for a reason.