Confused about re-pinning 74 Gauge Cluster Connections to a 78

[Gregski]

putting in a 1978 gauge cluster with a tachometer into my 1974 GMC 1/2 ton that had gauges but had no tachometer

found the ORIGNINAL CLUSTER CONNECTIONS chart (thank you HATZIE) but am confused about repinning two things specifically

IGNITION - on my '74 two pink wires go to pin #5 and #12, on the new '78 cluster somehow three pink wires need to go to #4, #6, and #12

however...

RH TURN - on my '74 a Dk Blue wire goes to pin #11 but on the new '78 cluster somehow it also needs to go to pin #12

so there is a conflict on pin #12, who wins, the turn signal or the ignition? LOL