You can't top AND bottom balance cells. You have to choose one over the other. That is, if you plan on using a large portion of the cell voltage range (3.4V - 4.1V). If you plan on using a shorter range (3.6V - 4.0V) then it is "possible", but difficult.
With your numbers, 27V would be correct, 13.5V * 2 (being lead acid 12V batteries). This is top end of the cells, not bottom. So using LiCo cells, voltage ranges with 7s is ~3.85V top voltage, and ~3.29V for bottom voltage. This is a very healthy range for your cells. Altho, you are loosing some capacity at the top end, but not much.
However, to answer your question, you need a bms to do it. And one that is configurable as the default for the cheap chinesiums are 4.2V/cell. So any bms that has bluetooth or network connectivity should be smart enough to be able to be programmed on the voltage ranges you want.