Calibration on Command Link

[fnb2327]

If my flow meter shows 50 gallons used, but my actual use is 53.5 gallons, to adjust my Command Link calibration do I use plus (+)7% (3.5/50) or negative (-) 7 %. Thanks.

[boats.net]

Need to check at least 3 trips and fill up's and use the average difference, if still same calculations then Set at +7%