Usually, the issue is that the 7th thru 10th seats aren’t actually 10-7=3 seats, but 4 seats. (the 7th, 8th, 9th, and 10th seats).
Of course they’re three seats. “10th” is not a seat, it’s a fencepost! If you want “the 7th, 8th, 9th, and 10th seats” you should say 7th thru 11th.
If you want “the 7th, 8th, 9th, and 10th seats” you should say 7th thru 11th
You should say “7th to 11th”; “thru” (i.e. “through”) specifically implies inclusion of the right endpoint.
(Although unfortunately, “to” doesn’t likewise specifically imply exclusion.)
Of course they’re three seats. “10th” is not a seat, it’s a fencepost! If you want “the 7th, 8th, 9th, and 10th seats” you should say 7th thru 11th.
You should say “7th to 11th”; “thru” (i.e. “through”) specifically implies inclusion of the right endpoint.
(Although unfortunately, “to” doesn’t likewise specifically imply exclusion.)