There's nothing wrong with your plan, loops are the heart and soul of programming aren't they? in the process you may discover something which will allow you to simplify or to remodel the job.
Personally in this case, without knowing too much of the problem, it probably is OK. If it performs well and is accurate then I wouldn't worry.
As for loops within loops, in general. If you have x loops within y loops within z loops. You will be doing things x*y*z. So as x, y, and z get large, the number of calcuations you are doing will get really large. IF you think of it as a function and graph it, your function would get large really quick. This is why people like recursion where you break things into groups like bubble sort for sorting. If this is interesting then check out Big O Notation.