tdtd, I was reading stuff from the link you provided. Kyp alone bounced Lke off the corridor wall and got Luke halfway to the floor. It wasn't until after that that Kun arrived to help Kyp.
"...I felt another presence. Not strongly, but it was there and it helped Kyp's next attack pack a wallop."
So you see, Kyp's first attack was only his power, not Kun's, and he got the best of Luke with his first attack.
Originally posted by tdtd
You're misreading, because those are quotes from Coran, not Luke. He was able to somewhat move Coran and Coran responded with "You're good Kyp but not that good". Then he felt another presence in the room as if Kyp's new mentor was guiding him, and the next force push sent him flying.