TBH i've never seen this happen, even w/ severely mixed ship-types. OTOH 90% of my ASW patrol TFs have their 3rd PZ-hex set to their home-port, w/ Full Refuel. query to the OP - are your PZ hexes set to Remain on Station for 0 days? if so, they will burn through their fuel v. fast, better IMO to set RoS to 1 day in each hex.
what does get up my nose, though, is that quite often my PZ ASW TFs will refuse to continue their PZ circuit after refueling at their 3rd hex - they stay at their base, despite having a valid patrol route, until i notice their inactivity. i have to X out their patrol route & re-define it, before they'll return to their duty. this only happens to my PZ ASW TFs, my PZ submarines always return to their PZ after they RTB for refuel/re-arm.
my TFs are set for 3 PZ hexes at sea, linger 0 days, no refuel at patrol hexes. The patrol zone are a few hexes wide. Fuel burn is not the issue, it´s the problem that they will stay out until being completely empty, instead of refueling at their home port, where plenty of fuel is available. This doesn´t occur every time, but every 10th or 20th occurance, and of course leads to damage to the ships, and the necessity to intervene manually.
< Message edited by margeorg -- 2/22/2013 8:09:45 PM >