CALC will use percentages by default with the "+" sign as additions. So that 0.9% + 5% == 0.009 x 1.05 and 5% + 0.9% == 0.05 x 1.009. As such the results seem incorrect for the standard percentage calculation where the results would be 0.9% + 5% = 0.009 + 0.05. Add ability to switch this behavior when needed...