Range/Room is everyone in the tower when you're in the tower. In flight it's everyone who took off from the same field.
Range and room text channels are two different things.
"Room (3)" is the older one, it covers indeed tower or (inflight) everybody who launched from the same field regardless of range. In older times, many players though this 'room' channel works like a range channel, which it did (and does) not - a source of constant confusion.
The "Range (7)" text channel is a relatively new one (~3 years?). It actually works like the range voice chat, but IIRC players have to be tuned to this channel to read it and I remember only few were.
