I should have said as the OAT increases so does N1% until about an OAT of 30C, then the N1% starts to decrease. This fact threw me off. N1% at an OAT of +50C is irrelevant.
I think I got it now. The assumed temp of +50C gives a lower thrust. To achieve this lower thrust at an OAT of -52C the FMC will have to decrease the N1%.
Ok, thanks Skyjob.