One factor is Rock Band ...
Although VGCHartz's game sales alone (probably) do not account for the PS3 having higher revenues than the XBox 360, but it is probably one of the main reasons both system's revenues are so high; when you're selling a game for (potentially) 3 to 4 times what a typical game sells for (because of high manufacturing costs) even smaller sales can dramatically boost revenue without adding a similar increase in problem.
There is (possibly) also regional considerations, where in Q1 they might have released games in Europe which sold better on the PS3 ...
The last consideration (partially related to RockBand) is that PS3 owners may be more willing to pay for digital downloads ... If the average RockBand owner is willing to buy twice as many songs for the PS3 as they're for the XBox 360, if sales were high enough this could be (very) noticeable on the financial statement.