In addition to this the TS are placed in various ICM bands on basis of data for quality collected in the last 5 calls (may vary as per vendors but this is a standard) on that TS. If there is any call drop observed in the last 5 calls history due to quality issues the TS is placed in one poorer ICM band.
Check the interference levels (DL & UL) and TA.
If there is a rise in poor DL/UL quality post swap then there is a chance that the new equipment is radiating more power (usually old equipment’s power reduces-e.g. it shows 43dBm but actually its less due to old equipment or antenna fault).
The same results in increase of interference regions as duew to increase of power the area of overlap reions increase and thus more calls face interference in comparison to last scenario so eventually the TS record pooroer quality bins in last 5 calls and thus more number of TS are mapped to poorer ICM bands.