@newbie-02: I also apologise because my answer was too fast and didn’t address correctly your question.
FP numbers are OK as long as you don’t meet the limits where it is impossible to have an exact representation of the number both in bases 1/2 and 1/10. There is a common subset between N and FP and it is adequate for accounting provided you opt for an adequate base unit (¢ vs €) and your numbers are not too large. If you take the precaution to always used integer arithmetic (within FP range) for accounting, you’ll have no problem.
I don’t think Calc is the right tool for “scientific” computing. Your 6.234e-27 hinted me in this direction. Numerical analysis tells me there is enough inaccuracy with method and computing (round/truncate) that I should not try to interfere with hardware FP result lest I add more inaccuracy and degrade the result.
This is perhaps where I did not understand your question.