Although the final number of possible mates was low, does not necessarily mean that it would take forever to find the other one. It statistically more unlikely but still can happen within a short period. - Good luck for Peter! :D
PS: DI did the same calculation too, some time ago but did not include an degree as an criteria but was even more picky in general. xD
It's just though to consider all the possible variables :) who know maybe publishing his letter gave Peter some popularity and helped him getting his date!
...maybe I should publish it too? :D
ahahaha if that makes you famous it will definitely help :)