http://efidynotuning.com/fuel.htm#scaling
You probably have to scale for the injectors too. I always recommend setting the injector high slope to 30.00 lbs/hr or (30/3600 == 0.0083333333333333 lbs/sec ) and scaling your tune based on your actual injector high slope / that value (30 lbs/hr). That way you know you'll never run in to a clip limit since the 64lb maf limit is just above the 30 lb/hr injector clip limit thus for any injectors you run (as a result) your injectors will go static (pegged out of injector flow) before you hit the airmass clip.
30 gives you the maximum resolution regardless of your injector size and allows the deltap multiplier to not clip.
When doing so you want to be sure to set the IDLMAF - minimum idle airmass clip (or the MINAM - minimum airmass clip in older ecu's) to 0 to prevent excessive fueling at low airmass flows due to the low airmass flow calculated.