To calculate the sum of ceiling values for two integers 'n' and 'm', the formula is ceiling[(n+m)/2] + ceiling[(n-m+1)/2]. The discussion emphasizes analyzing two cases based on the parity of 'n' and 'm': both integers having the same parity (either both even or both odd) or having different parities (one odd, one even). In both scenarios, the ceilings can be explicitly determined, leading to a clearer evaluation of the sum. It is noted that the sum or difference of two even numbers or two odd numbers is even, while the sum or difference of one odd and one even number is also even. A key takeaway is that in any case, one of the expressions results in an integer while the other results in a half-integer.