Are you confusing a drop away rest with a shoot through?
If your useing a shoot through (TM Hunter is a shoot through...unless they now make a drop away rest with that name as well) Having a low spring tension isn't all that bad.
When you draw the bow, I would suspect that the arrow will have plenty of tension to hold it. If your a brave and trusting soul, have someone draw your bow, then feel the amount of tension holding your drawn arrow. If your not that brave or trusting...you draw the bow, and have someone else bounce the arrows
Remember, at rest, the rest needs to support most of the weight of the arrow, and deal with the added leverage of the heavy part of the arrow being another 20+' from the rest...when drawn, it needs only support about 1/2 (the other 1/2 is supported by your fingers/release).
Short version, if it's shooting good, leave it alone <img src=icon_smile_big.gif border=0 align=middle>