[JLS]

but the rest I didn't automatically consider the open seats or special election as Republican like you did.

Well they are seats currently occupied by a GOP member of the House. That means the GOP has to defend them or capture other seats to gain seats. In addition the "special election seat" was last occupied by a member of the GOP. So again the GOP must win that one or the GOP caucus shrinks by one seat.

[airborne]

Just explaining how I came to my (inaccurate) numbers.