I used a 16 -20 week fertilizer on commercial properties 2 years ago where I was there 7 times a year anyway.. I applied it in may and it lasted all summer till September.. We were able to spend more time concentrating on spraying nutgrass and cracks etc this way.. Since it was a route where we drove over a 2 day period to cover each route it also helped by carrying less products on the trucks.
Residential customers in my area want to see a fert everytime you are there.. So this extended release fert wouldn't be good for them in my opinion, but I love using it on commercial properties.