well, there isn't much to discuss beyond what we already knows anyway. Manga is pretty slow in this that sometimes even I doubt this manga fit the romance tag and the mangaka even joke about it in the extra corner in some of the volumes.
Personally, I think the series would have done even better sales-wise (it already doing pretty damn good at about 200K but not at Kimi Ni Todoke, Nodame level (850k-1mil) which I hope it would) if it focuses a bit more on the romantic side.
But like you said even with all the facts being shown, there are still some weird gap in time line.
Anyway that is the only thing I can come up with that make sense, and as for 7th grade, he might simply missed the tournament due to his grandpa's illness as it's being implied that he missed some tournaments before his grandpa's death and after the death he ceased all activity until now.