I know I'm coming at it from the outside, but having checked into the EXPRES test extensively, it seems like shifting to a task-based standard makes more sense. The reasoning is probably that any arbitrary number of pushups, situps, grip, step, etc. is necessarily an abstraction. The number of push-ups that any given member can do is necessarily an abstract, and therefore impercise measurement of their overall upperbody strength. Therefore, the EXPRES test is only a predictive tool.
A task based test, the FORCE test, removes a lot, if not all of the abstraction, and would theoretically be much more predictive of whether or not a member will be able to accomplish a task likely to be assigned.
For example. Picture that short skinny guy who weighs 100 pounds soaking wet. Such a member can probably run like a gazel and can crank out push-up after push-up. But, because his relative muscle mass is going to be a lot less than the guy who weighs 200 pounds and is solid muscle the former member will probably have a very hard time dragging a fully-loaded infantier with a sucking chest-wound. He can do a staggering number of push-ups, but his muscle mass isn't necessarily going to be enough to drag a wounded soldier. He moves comparitively low body-mass in a push-up. When a task calls for much larger muscles, he might not be able to accomplish it.
Compare with a 200 lbs mass of muscle. He probably can't crank out as many push-ups as a lighter bodied individual. But can he drag the casulaty? You betcha!
So as far as a predictive test is concerned, any test which measures only an abstract level of fitness probably isn't going to be the most effective measurement. Moving to a task-based test seems to make sense. This probably isn't going to be "fit enough" for the combat arms, but as a minimal standard of fitness, it will probably be more useful than an abstract measure of fitness based on relatively arbitrary numbers.
Nobody's ever said, "There's a flood in St-Jean! Quick, do push-ups!" People have most definitely said, "There's a flood in St-Jean! STACK SAND BAGS!"