The satellites are co-located, sharing the space, and are mostly listed at 28.5E.
I doubt your problem is an alignment issue, especially as you get a very good signal on all other channels, although I can't see any signal quality readings posted.
Personally I think someone has posted a possible answer DECT interference, or another source, of interference.
You could test this, and other possible problems, by checking your receiver closer to the dish, outside, by running a new, shorter cable, from your LNB, to the ground, and hook it up to your receiver, and a small TV, or computer monitor, which has a HDMI input. Of course you need some decent weather, to test this.
An easier test is to check your receiver, on another dish, friends, or family members, check the two missing channels and note all the signal quality readings.