Hello VW user,
I am the developer who is responsible for Seating Section implementation. I see what are your concerns and I know for this problem.
For now, we have a command "Number Seats...". You can access it from the context menu(right click on the seating section). The command is not a big deal. Just gives you the possibility to renumber your seating section, manually. The command is slightly improved in VW2018. For some SP or VW2019, I think it would be a good idea to add automation for this numbering command (it could be similar to the "Number Instruments" menu command). If you have any other question or wishes, feel free to post them.