In theory what u wanna do makes sense the only downside would be say u transfer all five vials into a 50ml jug and pull a sample from there the only down side would be is if you whind up with say another mast p vials and the rest primo or something along that line. Then ur kinda stuck with a primo e and mast p blend which isn't the end of the world atleast ull know for sure what u got and also at what dosage.... So as long as ur okay with possibly having a blend maybe it's not all that bad of course if ur okay with the blend. But it's a good idea and atleast ull know exactly what ya got for sure..... If u do test man I hope the best for ya... I'm gunna be ordering some primo ,test c and e, deff some tren hex,alil npp, and some tbol or mast e.... It sucks this happend on ur first order iv been using Stan for a few years now and everything has always went really well. Glad he did ya right in the end, and you always have another two very soild srcs here.....