I'm in agreement with Stecal's underlying concepts even if I would word it in a different way

Putting in the rear mirror the fact that you shouldn't be using RBS, increasing the size of RBS_04 will solve nothing, transaction will most likelly use a different RBS next time it executes.

Root cause of ORA-01555 is not the size of the RBS per-se but the inability of getting a consistent read. To minimize occurrence of this issue while you plan your exit from RBS try this...
1- Create a new, large RBS, call it RBS_BATCH
2- Assign offending transaction to RBS_BATCH