Of course you can.
I reacted to this: "what if a person joins partway through the season? If the year goes for 4 full seasons, will they have the chance to finish out the 4th season, or will the term end exactly 4 seasons from the team's creation?"
I feel it bigger "problem" to expire mid season than starting mid season and I think my way could solve this (both).
Also I'm pretty sure that lots of people wanna try this feature and it's kinda annoying that you start in the beginning of the first season and - because of the 1-year term - your team will expire just before the 4th season's PO. If someone will be like "ok, if I get to the second division this season, I'll extend" it's pretty not fair that he has to buy another 1 year because of that 4 weeks.
To me it's really just a theoretical question but some others might be thinking like this.
Don't feed the troll