Maintaining BLEN attribute of DTAB

Is there a way to modify the BLEN values of DTAB other than every time modifying the whole entries using the command similar to BLEN (10 15 20 25).

Is it possible to append a new length(also modify values in between) with out disturbing other entries.

Is there a way to modify the BLEN values of DTAB other than every time modifying the whole entries using the command similar to BLEN (10 15 20 25).

Is it possible to append a new length(also modify values in between) with out disturbing other entries.