We do allow 4 tens for some positions. Our Public Works all do 4 tens and they alternate which days they get off. So some get Mondays off and some get Fridays off. We also have some in city hall that work 4 tens. It depends on if they have coverage on the off days to be allowed to work 4 tens. We have some that work 5 eights because they don't have coverage in their department. In the HR dept I have 2 employees that do 4 tens, one takes mondays off and the other fridays. I work 4 nines and a 4 hour day on Fridays. I chose this schedule because I was getting called and working on Fridays anyway.
Because we have a variety of schedules in one building we have had morale issues due to this. We have also had issues with coverages over the years, for example when an employee is off for their Friday and another employee calls in sick. We have considered taking away the 4 tens option but know that also would hurt morale. I would say employees having flexibility has been huge for employees. However, we have also found employee that work the 4 tens don't truly work ten hour days. Most come in at 7AM but our offices don't open until 8AM. There have been concern about people not actually working that first hour. Working on solutions to combat this.
We still pay 8 hours for holiday pay. Those that work 10 or 9 hour days are required to make up the time or use vacation. If the holiday falls on the employees monday off, they typically have the tuesday off that week. Which again can cause some coverage issues.
We have been doing this since before I started. So I'm not sure about the impact it had on culture.