linear advance v1.5 problem

I am having problems setting up linear advance v1.5. The printer is calibrated perfectly and without linear advance enabled the prints are really good apart from a few small blobs. I have followed the instructions on the marlin site and watched the video by teaching tech on youtube but after setting it up the top and bottom layers now are not connected to the sides of the test cube. The. best line from the test print was 0.20 ive put that value in the firmware rebuilt it and flashed then m502 m500 and m501. i am not sure what i am doing wrong

Thanks Nikki

A better place to get advice on print quality issues is the reddit community "fix my print" [www.reddit.com]

Thanks Ill have a look