The question is how much time is spent maintaining and testing for correctness a portable program in it's early iteration vs the time spent porting it for it's

The question is how much time is spent maintaining and testing for correctness a portable program in it's early iteration vs the time spent porting it for it's second lease of life. Clearly if it it would have cost 2N dollars to obviate N dollars of work, then cost would not have been worth it. This can occur if either a) portability complicates things a lot or b) it complicates things a little, but over a very long timespan during which maintenance work is being done.