The ones that let you order 200 only let you order that amount once a month. In the end it works out the same really don't it? But the main one I know that lets you order 200 at once charges higher prices so it works out cheaper to get 100 twice a month.
However, there is absolutely nothing stopping someone from ordering at multiple pharmacies (except the size of their pockets).
I also find getting only 100 each go makes me use less. If I have like 500 in front of me I will bosh an entire box of 100 within a weekend. 100 every two weeks though and I make that 100 last two weeks.
Mostly I'm amused that these pharmacies are actually getting more lax, not less. Since the media noticed they exist the regulator did as well. I thought this would put the heat on them and make them stricter. Instead they're actually letting people buy more!