I wouldn't play w/ it- the low temp differential will actually contribute to a tighter bract set. It's certainly not going to cause any problems.

You may, strain dependant, see a slightly longer maturation time, w/ a corresponding increase in weight. ( Actually, ratio will skew to weight...:thumbsup

If yer really concerned about fungal issues, you might want to think about prophylactic applications of sulfur or subtillus- strain will come in denser @ low delta-T.