My own take on productivity was/is that it means very little within the context of a watch keeping role and it cant be directly translated to a deskbound role even within the same service. How that can them be measured at a service granularity is beyond me.
Anecdote time.
I worked double days at a day only flying station. earlies started 1 hr before ATC which in turn started 1 hr before flying. Normally then 6am, but we finished at 12am a short day...which compensated us for the following... Afters started at 12 until cease flying which could be 8 in the summer, additionally the afters shift covered out of hours stuff and the following weekends display work.
Days did 8-5.
On change of boss, the decision was made that we (shift workers) weren't working enough basic hours compared to days, so mornings were extended till 3pm and afters finished at 8pm even during no flying periods or later as flying dictated. Given that the out of hours stuff was watch keeping, but the staff using the equipment had gone home, there was actually no work to do..
I don't mind working, but I don't like being shafted simply because somebody further up the food chain cant equate fair and reasonable. Whacked in my environmental and was posted within 3 months.