Don't listen to this guy. Either they have changed it since this post was made, or this is just flat out misinformation. I have been looking for info on how much it costs (roughly) to get a tactics page up to level 3, and this is the only info that I found, so I went with it. Unfortunately, it is not correct.

Just now I have upgraded my tactics page a total of 14 times, which costs 350 coupons (25 coupons per 1 try), and I am still at only level 2.

God knows how much more it will take to get to level 3, at this point I am afraid of spending any more. But even if I were to get it on my next try, that would be a total of 375 coupons spent to get to level 3, which is much more than 220-250. Probably you can expect to spend around 400 for level 3, but maybe even much more than that. If anyone has the correct values, that would be very helpful.