ShadowHawk: Using your standard UK1 Taranto raid with no extra sub here are the two scenarios:
Scenario 1) No Scramble
UK loses one unit
Italy chooses to destroy the French fleet because it is difficult to kill the remaining UK fleet in SZ97
Italy loses most of their income on I1 from convoy raids, and doesn’t get any bonuses
Germany loses 2 or 3 planes when cleaning up the Med on G2
Scenario 2) Scramble three fighters 60% chance that UK still wins, likely keeping a bomber, tac, and fighter that can land in Malta with no fleet left in SZ97
Italy destroys the French fleet, maybe losing one more ship than in the previous scenario but those ships don’t make much of a difference in the game
Italy gets bonus from have the Med cleared of ships, has no convoy raid, and is in a similar strategic situation as scenario 1 since the additional income makes up for the lost fighter.
20% chance that Italy wins and keeps the transport and possibly a couple of planes
Italy is extremely strong and can threaten Egpyt. Even if UK holds the territory, they are prevented from aiding Russia for several rounds. The Axis are in such a strong position that they have a very high likelihood of winning the game. I usually surrender as Allies if Egpyt has been captured during the first few rounds and there is no chance to recapture it.
20% chance that UK crushes the Italians without many loses
This becomes similar to Scenario 1 except that Italy has two fewer planes for the rest of the game. While this is hardly your preferred outcome, you aren’t scratching your head trying to figure out what to do for the rest of the game like a situation where Egypt falls on I2.
Summary:
60% chance of similar outcome to no-scramble
20% chance of being in a very strong position
20% chance of being in a slightly inferior position
Throw in other considerations and scrambling might or might not make sense. So much depends on your gameplan for Axis.
Adding in one extra UK sub will tip the outcomes to about 50%/7%/43% for similar/great/slightly bad. No thanks to that scrambling opportunity. It is very likely that the extra sub will survive until UK2 where it can wreak additional havoc in the Med. With support from a bomber and other planes, it can destroy or damage remaining Italian fleet. The net benefits are way more than 6 PUs.