1) Capships take time to recharge their subspace drives (as was mentioned before). 6 times on the same mission would considerably extend the time said mission lasts.
2) GTVA jump drives are supposed to lack in precision. Such maneuvers would be hard and risky to pull off once, let alone 6 times.
3) May be tricky to implement (as was mentioned before).
4) Sounds like it will probably result in a BoE'd mission.
5) Defies Shivan, GTA, PVN, GTVA and NTF tactical doctrine as evidenced by the fact that, in decades of almost constant war, it was never done before. Not even once. Not even against the Sathanas (and the Phoenicia really could have used it.)
But hey! Your mission, your rules.
