Is this length reasonable as balun ?

Attached figures are from hobby level RF circuit book.

It says that this circuit works as balun with narrow band.
It consists of 1*λ transmission line and λ/4 coupled line.

However I can not understand why it uses 1*λ transmission line.
I think it has to be λ/2 transmission line.

How do you think ?

Looks like a Compensation Circuit in order to align the phase but the Lambda seems exaggerated..
It should have been between Lambda/2 and Lambda..It might come from physical layout too ( we don't know yet )

Maybe there is a practical layout reason to add another lambda/2. Narrow band, it makes no difference.