OP, I hope you are taking my participation in this thread as intended, which is to be helpful and provide info that might be useful in the future.
As far as recommended temps for yeast are concerned, yeast manufacturers are a lot like kit makers when it come to their recommended temps. They want to tell you that it's okay to ferment at temps that you can achieve without a lot of fancy equipment. Some yeasts actually do work well around 70F. But there are even more that say 70F is in their range when in fact they taste much better well below that.
The yeast you used if for hefeweizen, and a lot of the time people want significant phenolics, in which case fermenting towards the top of the recommended temp range is the right thing to do. But that yeast produces phenolics no matter what and you'd probably get all you wanted fermenting at or below their suggested temp range. If the bottom temp was 66F I'd probably ferment at 65F. Not always true, but the lower you go the cleaner the beer will taste.
I make mostly English style ales and use English strains of yeast that have a tendency to produce a lot of esters. The esters are part of the style and they should be there, but I certainly don't go out of my way to get as much as possible. The esters will be there. I use WY1469 more than any other yeast and they recommend 64-72F. No way in hell I'd ferment with it above 70F. I try to pitch at 60F and let rise to 63F where I hold it for 3 days after active fermentation has started, then let it rise to 68F for the duration, until I cold crash it. When I enter beers from that yeast to competitions the judges frequently note that they can taste the "traditional english yeast character" which is good. But I am sure if I were to ferment high they would mention that the esters were overpowering, which would be bad.
Long story short, unless you're really looking to boost the esters and phenolics, consider the low end of the temp range to be the optimal temp for that yeast, if not a little below that.
The reason they don't list lower temps is because they don't want unhappy customers with batches that had extra long lag times or that didn't attenuate fully. But if you know how to work the yeast (good pitch rate, good aeration, precise temp control) you can get very good results below their recommended temp range.