Hmmm, maybe I was wrong about being wrong!

I know its a crazy thing, but entering "custom line" as search terms into a SEARCH in the .pdf version of that little thing called a contract yielded this as a result!

Teach a man to fish......


Sec 25.G. Open Time Assignments
1. Following resolution of phase-in conflicts, open time may be
used in the following order: training assignments, phase-in
make-up (including MUV, as provided in Section 7.G.5.a.), and
then substitution/reassignment. Remaining open time shall be
used for construction of secondary and conversion lines. After
construction of secondary and conversion lines, open time may
be used at any time prior to or during a bid period for PMU,
substitution/reassignment, custom line construction, advance
reserve assignment, advance volunteer assignment, make-up,training assignment and Association Fly Back (AFB). However, during the first 12 hours after the publication of open time, only
pilots shall have access to open time trips starting in the new
bid period. The Company may also use open time before the
assignment window in order to assign a trip to an R-24 pilot.