At this point, the game has gone on so long that I fail to see the massive statistical difference you would get from having, say, eight IPC instead of four on G1. It really just comes down to the tactical errors your opponent makes, and how well you take advantage of them, be they ever so slight.
The massive difference of bids 4 and 8 can mean taking Egypt with enough to deter a counterattack or can mean 2 extra units deterring or thwarting an attack on Ukraine. If Egypt isn’t to be countered, then the UK has all sorts of options. Still, it comes down to the dice - you have a point that it doesn’t always matter 4 to 8 and so on. With two units to Libya, Germany can expect to take it with 4 units plus their plane(s). With just one unit to Libya and good rolls, they could end up with the same 4 troops sitting in Egypt.
But its simply usually enough for germany to shred africa with minimal investment, hold it until the US is forced to divert troops, at which time Japan has spread the rising sun across the entire swath of the southern pacific and the indian ocean, and is usually able to reclaim the dark continent for axis hands, while at the same time putting the serious hurt into Moscow.
How are the Allies managing Africa in your games? Is Germany taking South Africa as America first lands Algeria? Africa is almost always the first place I go with the US and UK. Lately the US has been in the Med for long term control. Unchecked Japan will definitely plow through Africa.