Yes, it's vague an "markets around" can mean anything in a system.
It's not as clear as one could argue, that one should have known that this means influence is only planetwise. Could mean "Planet a, a1, a2, ..", or the system, maybe the further away the less, but the bigger the station the... or whatever.
Because this was not specified, I had a look in a lot of other "old" planets - to copy that in case.
Penadak f. e. has an industrial/extraction station at a not landable high metal content planet and the only other building in system is an industrial installation.
Gebel f. e. has an agricultural station at an earthlike planet, not landable, agricultural buildings are at B7.
Maybe FDev should've told us, that Elite-Planets in Colonization have nothing to do with Elite-Planets before - and some more information rather than "markets around".
Now we should test a beta and give feedback, but we don't know how it's intended to work so it's hard to say if it works as intended - over and beyond, the delay of processing all the new buildings makes it even more mixed up.