My Ntc3 deans had less connection all the way in then halfway in. The sanding flattens the gold plating surface for more surface contact between male and female plates, just like sanding ball diff plates gives better grab... No way to know if your deans connector pins are fully flat: I say sand them a little to guarantee a better connection between two flattened/cleaned pieces of gold connectors. Yes, you can also use some e tape, but only after sanding a bit...
I had low to no connection before sanding the deans connectors in my Ntc3, and great connection afterwards. That should tell you guys that sanding works, period... Yeah, you can also use electronic cleaner, etc, but only after sanding...
I can also add that it takes slighly more force to pull the deans connectors apart after sanding too.
Furthermore, I had glitches coming from a futaba transmitter once. I was ready to throw it away until I decided to sand all my AA batteries&transmitter springs/tabs , and voila, no more glitches: $100 tx saved + no new radio to purchase....