1) As we are using in our n/w, min 4 E1 subts needed for edge, it cant be increased more than 4, for gprs it 1 and for cs3/4 its 1.
2)for 2/2/2 its 2.25*6=18 + 3, so 32 – 22= 10 so 2 edge channels + 1 gprs channel at max only if u are not using any HR, otherwise u will get E1 constraint.
3)4/4/4 site , 2.25*112=27 , +3 for signaling, so 32-30=2 TS left on E1.
1 trx take 2.25 on the E1 hence this calculation, hope it clears your question.