Michal,

you replaced a variable in the index by a constant!!! That significantly reduced the complexity of the effective address calculation of that long long expression. With lack of further information (mainly how the library functions called from the published snippets look like, but also the end of the first for cycle in the first example) that is the main suspect - see those "push calib_x"-s... (I see no pops, but that might happen in some of the library functions - you should check out; also, the potential stack overflow can occur here).

What happens, if you in the first example replace ALL occurences of calib_table variable by the CALIB_TABLE_2 constant? (or, conversely, what happens if in the second example you replace the constant by the variable?)

JW