Will I have trouble running a bathroom fan 10 CFM (25%) stronger than needed?

My bathroom measures in at 289 cubic feet. Dividing that by 7.5 and rounding up gives me a target fan capacity of 40 CFM. However, there are many more fans available at 50 CFM.

I read this post, Are there drawbacks to installing a stronger bath fan?, stating that a fan moving more air than necessary can inhibit appliance fumes from venting properly, not the mention the HVAC efficiency hit from expelling conditioned air.

My question is this: will increasing from 40 to 50 CFM create such problems, or is that in the realm of a much bigger increase?