This article explains that why data size is displaying difference between Transferred Volume(MB) and Target/Source table Table.
Customers wonder why data sizes show differently
All Replicate version
1. Transferred Volume(MB) size in Qlik Replicate
2. Target/Source Database
1. The data size Replicate read (and process) may be very different from the actual size of the data in the DB. For example, a string column may be stored in the DB in specific encoding, using XX bytes storage. However, Replicate in most cases request the data in multi-byte in order to avoid NLS issues, which might lead it to read twice as much data.
2. Data Blocks, extents and segments in table may by difference before/after transferring data from source table to target table depending on Database and Journaling file system