Upgrade to 11.70 from 11.50 results in low Read Ahead Utilization

I recently upgraded from 11.50.FC3 to 11.70.FC3. As expected, the upgrade was painless and there are no apparent issues as a result of the upgrade. One thing that I do notice is my Read Ahead Utilization (RA-pgsused / (ixda-RA + idx-RA + da-RA)) is in the toilet after the upgrade. Pre upgrade - 11.50.FC3 - 99.05% RA_PAGES 128 RA_THRESHOLD 32 ixda-RA idx-RA da-RA RA-pgsused lchwaits 3724876 4323945 321113 8290237 3197641 Post upgrage - 11.70.FC3 - 15.14% AUTO_READAHEAD 1 # equivalent to RA_PAGES 128, RA_THRESHOLD 64, right? ixda-RA idx-RA da-RA logrec-RA RA-pgsused lchwaits 0 35100202 136980 0 5334831 1114786 My Read Cache Hit % has not suffered, it has even increased from 95.45% to 98.84%. I believe this to be a result of a new Auto Light Scan feature and some reconfiguration of buffer pools I did as part of the upgrade. Changing AUTO_READAHEAD from the default to AUTO_READAHEAD 1,16 has increased my RAU to 25%. I'm pretty sure this increase in idx-RA is a result of enabling BATCHEDREAD_INDEX and not a cause for alarm because performance is fine. Just curious if anyone else running 11.70 is seeing the same thing and if the recommendations for RAU at or above 99% needs to be modified when BATCHEDREAD_INDEX is enabled. Thanks, Andrew