You lot really need to read up on this before posting such drivel. Of course there is a cost to removing existing seats but crowd capacity will increase due to the smaller seats that would be put in to comply with UEFA and for concerts etc. So ticket prices will be reduced especially in the long run. Don't forget the existing seats are wider and padded for our comfort you would not need this for other gigs etc.
Isn't the point of safestanding that they also work as seats for when all seater is needed? Making the seats narrower and less comfortable seems to go against the attitude of the club wanting to improve the match going experience. The comfort of seats is something of which the club are proud, they are not about to stick us all with 18 inch wide planks of wood.
Also, I did some reading, as you suggested,
These are the fifa requirements for stadium safety and security.
http://www.ffu.org.ua/files/ndocs_443.pdf (skip to page 36 of the document/(38 of the pdf))
It says you need to look at:
a -The number of seats you can fit in minus those that can't be used for whatever reason (restricted view, damaged, used for segregation, etc.)
b-the number of people you can get in per hour
c-the number of people that can exit the stadium in a reasonable time no greater than 10 minutes
d-how quickly the stadium can be emptied
And the lowest of these figures is your maximum capacity.
Add all the seats you want, it won't matter if any of the others are lower.