I disagree that fermentation temperature has any effect on attenuation. It will attenuate faster at higher temperatures, and slower at lower temperatures, but given enough time at either temperature will still end up at the same point either way. At 64 F ambient, that's just about perfect, not too hot and not too cold. Don't mess with it. You did good. It's just done, that's all. See my previous comments. Ferm temp affecting attenuation would not be consistent with my experience at all, not with most yeasts anyway -- very very few exceptions -- maybe Belgians are more fussy, but they are the extreme exception. With 1450, this shouldn't be an issue at all.