Quite sure, it was discussed in detail.

There's no look back in the sense of "How much have you used this year, and does that mean you have to verify?"

The "free pass" on that verification--i.e., "Did you use less than 50 hours each of the past two years?"-- does look back, so that on 1 Jun 17 (the start of our first full sick year under the new contract provisions) & forward, the 50/year/last 2 years does apply. I agree with Sailing, that's to our benefit.

Only caveat, this is how it was discussed at the roadshow. If actual contract language implementation differs, that will a different discussion.