Full decos (and by that I mean the deco range e.g. Cliffes and Holdens and Bowllys, NOT non-deco shoes that are made to the deco last) are by definition MTOs - their price is on a one-off basis and so they've never attracted an MTO "surcharge".
Full-deco pricing, as far as I can tell, remains the same because there is no MTO surcharge to waive.
Deco-lasted shoes, on the other hand, DO qualify for the MTO surcharge waiver.
So for example, instead of getting a Holden (full deco) at normal deco pricing --
you could opt for an Oxford (non-deco) on the deco last and take advantage of the MTO surcharge waiver.
It is purely a matter of personal value whether the additional finishing and construction details of full deco are worth the price differential. With the October offer, the differential simply becomes larger.
Also bear in mind that the full deco price includes shoe trees. Deco-lasted MTOs do not - you will have to add shoe trees (£150 for EU customers) if you want them.
Hope that helps!