Onyx will average your results. Once you measure all of your calibration or ink restriction targets, onyx will show the window with all the measurements, but now it will show all measurements so if you have 3 scans, it'll have 3 values for 1 patch. press next and it'll average.
Because onyx uses gateway internally. I don't think they have much control over it.
How ever if you do get a bad scan, wait until it finishes that page, then when it asks you for the next one and the screen goes to the next page, just click the page you need to rescan (at the top) and press scan or measure (what ever the button says)
I'm not sure how you're getting a bad scan with the LFP? is your material moving? What aperture size?