just to reiterate:
DVDs have 2 "locks" on them 1) the region code and 2) the format
many dvd players are both region and format locked.
yours is simply region locked.
this means you can play both formats, but only if it is the specified region.
you have not been able to play your originals in the past because it has a region different from what your player is locked to NOT because there's a format incompatibility.
by using dvd shrink you made a REGION FREE PAL backup of your original disc. you can now play this on your standalone because there's no region lock on the disc...it works with ALL region players.
it says NTSC only on the box probably because of what I said before...it's a mass marketed piece of electronics. rather than change the hardware capability to sell to different countries they did a huge production run of multiformat players then region locked them to whatever region they were being shipped out to. as we all know, it doens't matter what it says on the box ESPECIALLY in regards to electronics.
and as has already been stated, computer DVD drives have no such region or format lock on them which is why everything works on your PC.