Testing is as for incremental maintenance. Existing test data and archive data remains unexpanded. Configuration management is simplified. Project is smaller. Arguments Against the Procedural Approach Date logic may be complex due to the need in some processing to cater for century rollover explicitly.
Ongoing maintenance is more expensive.
As more and more interfacing systems carry 4 digit years, bridging requirements will increase. Procedural logic for century rollover may have greater processing impact than extending the data items. Sort complexity may be increased. Additional processes may be required for other ordered constructs such as VSAM files. Some dates in key fields may need to be expanded selectively.