Traditionally for every branch re:ROTC scholarship, if the school says FT it takes 5 yrs to achieve the degree, they will give 5 yrs.
The one finesse issue to understand is something we found out last yr. DS learned when registering for spring sem. jr. yr. that the school had him graduating in fall sr. yr. because he had fulfilled all of his requirements for the degree. (This would have been a semester early). Due to the scholarship requirements, he had to go from a major/minor/core to a dual major/minor/core to fulfill his ROTC lab requirements and scholarship.
Kids these days seem to be taking more and more credits, leading to graduating earlier or with a jt Bachelor/Master degree in 4 yrs. ROTC students need to work with the academic advisor and their ROTC instructor. Other wise your child can become our child, scrambling to figure out how to maintain ft status when you academically are done.
Also, for anyone entering the engineering portion, remember if you elect to go from a tech major to a non-tech major you need to get approval to keep the scholarship.