Note the change in room and building.
repeat with monthNumber from 2 to 12
-- start with the first of Feb through Dec
set firstString to (monthNumber as string) & "/1/2018"
set firstTime to date firstString
-- we want the last Tuesday (which is a 3) of the previous month
-- so subtract 7 days if the first is a Tues, and 1 day if a Wed
-- which means the math is as follows
log firstTime - ((((3 + (weekday of firstTime)) mod 7) + 1) * days)
end repeat
(*date Tuesday, January 30, 2018 at 12:00:00 AM*)
(*date Tuesday, February 27, 2018 at 12:00:00 AM*)
(*date Tuesday, March 27, 2018 at 12:00:00 AM*)
(*date Tuesday, April 24, 2018 at 12:00:00 AM*)
(*date Tuesday, May 29, 2018 at 12:00:00 AM*)
(*date Tuesday, June 26, 2018 at 12:00:00 AM*)
(*date Tuesday, July 31, 2018 at 12:00:00 AM*)
(*date Tuesday, August 28, 2018 at 12:00:00 AM*)
(*date Tuesday, September 25, 2018 at 12:00:00 AM*)
(*date Tuesday, October 30, 2018 at 12:00:00 AM*)
(*date Tuesday, November 27, 2018 at 12:00:00 AM*)