Canada Post works the same way with 30-60 days to send in your cover(s) to the Philatelic Centre and ask for and possibly pay for (I haven't done it myself yet) the stamp and cancel.
As the FDOI cancels in Canada are now directly related to the stamps (a tiger stamp has a tiger cancel) (yes really and truly we had tigers in Canada. The beavers ate all the grass and trees so the tigers had no where to hide when stalking game (the beavers) so starved or moved to India).
This makes for good marketing and sales as you get a more totally fulfilled tiger experience by having not only the stamp but a special tiger-related cancel and possibly an official FDC with more tigers on it.
The skill and craftsmanship of actually making a first day of issue cover has been laid aside to sell more and more efficiently and cost effectively (craftsmanship costs).
The marketing pushes the idea of a greater fulfillment (thus the name of your stamp center) to be had by having as many tigers as you can handle. More is better rather than the appreciation of individual craftsman's skills (some being better than others of course).
Everybody wants a tiger? Well we will give everybody some tigers then. There's gold in them there hills.
The appreciation of skill or even artistry by a master class craftsman is sadly lacking. Still to be had, rare and hard to find, but worth the effort.
If you hear and see marketing long enough and constantly enough you will start to believe it. people copy what other people are doing, or at least come over for a look see. natural human behavior.
It is up to the individual at all times to make the choice for themselves to choose whether appreciation of a personally owned piece of art or craftsmanship is worth it or whether a mass produced piece is good enough. Both are good in different ways.
What wt1 is doing is taking the mass produced cancels and adding the personalization of his own cover to the mix. I like doing this also but have personal problems with my printer and it's attitude about holding envelopes straight when printing on them. Still working that out.