Chase has only had one "bad" loss this year in the quarters (#37 Watt of ND) at the ITA Midwest regional. In the All American he lost to Rhyne Williams of Tennessee, however I don't see that as a bad loss since Williams just won the ITA Indoors. Re. doubles vs. singles yes you are right about the difference and pKobelt is much more dangerous in doubs.
Singles has become a baseline game, doubles is all about serve, return, dominate the net and volley, Kobe's height and skills transform very well to that style of play.
When Allare and Shuhei were matched together, Shuhei would sometimes come up with some big breaks with his return of serve, however his weakness in holding serve became a liability and Tucker finally made the switch to Koberlt and Allare.
I think it was a brilliant move and we will see the dominance this year of this tandem.