curious as to what 3% down program offers no PMI?
In addition, you state "low utilization". What percentage are you at?
You want to make sure that exactly one card reports a small positive balance (e.g. $15 -- higher is OK if it is < 8% of the card's credit limit) with all other cards reporting zero.
Based on what you say above, there might be some months when both cards report $0 (bad for your score) and some months when both cards report a positive balance (less bad but not good for someone preparing for a mortgage).