How are you getting 2x2 from two weapon fighting?
I think he was mistakenly thinking that TWF, on its own, doubles all your normal attacks and ITWF/GTWF add extra off-hand attacks on top.
For the sake of clarity, it should be noted that the correct attack sequence, presuming +6 BAB, TWF, ITWF, Rapid Shot, and Flurry of Stars is +6/+1 main-hand as iteratives, +6 for your standard off-hand attack, +1 for your extra off-hand granted by ITWF, +6 for the extra granted by Rapid Shot, and +6/+6 for Flurry of Stars. You'd suffer a total of -6 to attack on all of these. For the sake of example, we'll say your ranged attack bonus is normally +11 (including BAB). With all these together, you'd have the following combination: 4x +5, 2x +0. It should also be noted that, while your main-hand attacks (from iterative) and off-hand attacks (standard off-hand and extra from ITWF) are obligated to follow descending BAB order (though, each hand is handled independently of the other), extra attacks from other sources (eg. Haste, Rapid Shot, Flurry of Stars, etc) are under no such obligation. So long as the +1 main-hand comes after the +6 main-hand, it doesn't matter what other attacks are before, between, or after. Same goes for the off-hand attacks.