Description of problem:
During cold merge, base volume size is extended to maximum, i.e. by top volume size + vol-chunk-size. This is a worst case calculation.
After cold merge completes we have to reduce base volume size.
Steps to Reproduce:
1. Run cold merge
Base is extended by top's size
Base to be extend by data in top volume +/- 1gb
Checked multiple cold merges, base volume is extended by 1gb chunks