Hmm, not sure whats the matter here. I am using the current Mathcad 15 M030 and using the sheet you just posted I get the following (the second call yielding L2. etc should not be necessary):
As options like unit system used, value of CTOL, compatibilty options, etc all are worksheet options the only thing I can think is that you are using a differnt version of Mathcad. On the other hand if I read correctly a previous post from Valery looking at his screenshot he got the same wrong results with MC15 M010.
Alan, which version of Mathcad are you using and have you ever tampered with the files associated with the unit systems?