I think that there is more to it, first of all there is drastic increase in Half Rate traffic for BSCs as there are more than 500,000 HO attempts per day with cause 27 and there are very few attempts with cause 26 that is from HR to FR.
I think DL Quality degrdation is linked to this increase in HR traffic .
and these very high number of attempts with cause 27 are because of very high values for Offset_CA_High and Offset_CA_Normal which are currently set to value 45 (4.5).