There seems to be a contradiction in the fluff and fiction. Start Ops p. 135, which appears to be more fluff than rules, says that only the L1 LaGrange point is "a valid jump point.". While clear cut, it has many contradictions:
1: Isle of the Blessed Book One Chapter 3: Uses the New Avalon-Sun L4 point. Page 2
2: Dawn of the Jihad: Case White uses the Earth-Luna L2. Page 91
I'm sure there are other examples, but those are the ones I can currently find. Since neither side seems to be "rules" I'm wondering takes precedence. Additionally, page 88 of StratOps doesn't say anything about only calculating to an L1 point.