Some metabolic measurement applications are simple. Others are complex - such as comparing metabolic rates across groups of experimental animals with different body mass ranges. The consequences of simplistic or mistaken analyses can be serious. Instead of doing bad science using canned, "black box" packages that make naiive mis-assumptions behind the scenes, you could be getting expert advice and doing things right. At the moment that's a lonely place to be in, but you'll soon have company, I promise.