Выражение встречается в следующем контексте:

In November 2000, the decision was made to relocate staff from the London Office.
The relocation was people centred rather than function centred. Jobs were relocated to locations that staff were prepared to move to. Staff were not required to relocate. Everyone was capable of being redeployed, and the relocation was voluntary. However, it was made clear that anyone wanting a promotion would need to move out of London. Standard civil service terms and conditions were offered in Sept 2000 – that is, payment for house move, level transfer, and protected London salaries for 3 years.

Корректно ли будет перевести level transfer как "повышение"? Может, есть более точный перевод?

Заранее большое спасибо.

Тут попробуйте. Похоже level transfer это именно перевод БЕЗ повышения в должности.