Personal tax FA 2011 - personal pension adjustment

guinea pig

Hi,
I'm struggling with two practice questions, in the Osborne workbook, giving slightly different solutions; when an employee makes a contribution to a personal pension plan, then that contribution needs to be grossed up, and is added to the basic rate tax band, to increse the band level. That's fine. However, I've just tackled a question, where the employee earns over £100,000, and it seems that not only is the tax band increased as before, but the gross contribution is also taken into account when calculating the personal allowance. So in effect they get the benefit twice? have I understood this correctly?
GP