When the major ports of TARANTO, or NAPLES, are captured by the Allies, they seem to give too high a level of supply, with coverage of 100% over large areas of the map.
There are two parts to the supply system, each hex has a supply level depending on how far away it is from supply sources and the terrain through which the supply has to pass and also an effect from the weather conditions.
The second supply factor is 'combat supply', which controls the effectiveness of units in combat (attack and defence), this is the most important supply factor, as it plays a large part in the combat odds. A unit in a 100% supply hex cannot fight effectively, unless it has 'combat supply' allocated by the player, so the hex supply values are not a primary supply factor, but have a lot to do with replicating the terrain and weather effects of the Italian Campaign.

The top image shows hex supply levels which look realistic for Italy in the spring (March 1944) and there was rain on earlier turns, although the weather is clear in this turn.
The lower image is the next turn and the supply overlay goes to 100% all over the supplied area, which just doesn't look right. Hexes are at 100%, irrespective of roads, or terrain, only NAPLES and TARANTO show this effect when at full capacity, when normally with supply from other ports the game shows variable supply, depending on terrain and access to the road net.
Two things might have happened, first the weather has stayed clear and maybe the mud effect has gone, secondly I was controlling the performance of NAPLES, as a supply source, by not allocating workers, but because the supply effects seemed to be working well, as the Allies have been hit by supply difficulties several times, I relaxed and started to put workers into NAPLES.
I don't know how much this is WAD, but it does't seem correct, as the other smaller ports seem to by OK with the required number of workers allocated, but TARANTO and NAPLES seem to go haywire.
This shouldn't be a game breaker, as it is 'combat supply' which rules the game and this is always short, but I am not putting workers into the larger ports to try and stop the over-supply effect.
This is not a tested response as I haven't played enough games, more of a hunch, but the top image is more like a realistic result, although US 34th Inf. Div., at the top of the image is now in such low supply that it cannot be given 'combat supply'. The advance stops here, unless I can get more supply and although I have captured TERRACINA, no supply is coming from that port, even though I put in workers and it shows 100% capacity (over-powered by NAPLES??).
The work-around maybe to shut NAPLES down, removing all workers, but that will take time to have an effect. If all supplied hexes become 100%, this negates part of the game where fuel-burn increases to provide supply over longer distances. This was very noticeable before NAPLES was taken, as the Allies came to a stand-still at TERMOLI, with supply being trucked from all the way from BARI and hex supply levels dropped below 25%.
The AAR is on hold whilst I check out the work-around and see just how many workers, if any, should go into NAPLES, these images are from a new game played only in 'Windows 7' to ensure that this is not a system issue.
However, it has been a great game, just off screen South of VASTO, 5 Axis divisions have be pinned against the coast and the battle to eliminate them is ongoing. Meanwhile more German divisions appear to cover ROME, so the AI is not giving in. [:)]


