On the TWS i was limited to 3 Time & Sales windows. I usually have 6 tabs up, and so i wanted 6 T&S windows. There are two buttons in TWS. File -> New Window -> Time & Sales ->> Option 1 (Time & Sales), Option 2 (Time & Sales - Multi Instrument) You can use the T&S Multi-Instrument as additonal T&S. Its doing the same job. You can have 3 of each; 6 in total. G
I think you also get more of those deep book windows available simultaneously in TWS for having more assets, lots of trading in the prior month, or paying for quote boosters.
Do you mean the Level 2 screen? Because I didn't hit the limit of Level 2 screens so far. I trade with TABs using the TWS groups. There are 7 groups, so 7 L2 windows is the maximum I have open. And it works fine without paying for anything extra. The only restriction I have seen would be the 3 window time and sales restriction