Thanks for humoring me.
I did a quick search on "regulateur" and you do not appear to be a vintage collector. Your 9 IWCs may be quite recent and probably have all papers and documents, rendering the Certificate unnecessary. But even if you were one of those OCD collectors who needs to have the Certificates, you would have to fork out €2,700. Not exactly cheap, but worth considering.
Now imagine that you have been collecting vintage IWCs for well over 10 years, and already paid a "nominal" fee for the Extract from the Ledger or, in case of the Mark 11, the Certificate of Genuineness, for all your IWCs, some of which actually went Schaffhausen so the Extract or the Certificate could be issued, e.g. Ref 325, Ref 666, Ref 866, Ref 812, Ref 9386, Mark 11.
And now, out fo the blue, and for no apparent reason (to quote Forrest Gump) if you want to have the new and improved Certificate, you will have to send all your 40something watches to Schaffhausen, and pay the new "nominal" fee, which if the €300 price per unit is to be believe, will end up in a grand total in the vicinity of €12,000.
The motto "if it aint broke don't fix it" should have applied. Was it broken?
This is why it matters.