SD,
In each situation, 56 HR TCH:
1/ Traffic = 26.83 erl, Congestion = 26.59% —> Very abnormal, congestion way too high
2/ Traffic = 35.62 erl, Congestion = 2.15% —> Normal
3/ Traffic = 50.49 Erl, Congestion = 54% —> Normal
In the first situation, I think the capacity you compute is not corret. Not all TRX are actually able to carry traffic.
(or all TRX are OK but they are able to carry only full rate, not half rate)
In other cases (2 and 3), no visible problem.