Hi Simka,
You are right - they are only counting tenants who purchase their own apartments as "tenants". So if a tenant buys a renovated unit instead, they will be treated like everyone else and have to put 20% down (instead of 10%) and pay two month's maintenance at closing (instead of one).
There must have been a flurry of activity after the 90 days were up - I ran into the sales agent putting up signs saying that they extended the sales office hours on the 90th day; I am so curious as to how many tenants made offers.