the reason is that -m 9710 is used to collide the RC4 hash, while -m 9700 should be *only* used when you are looking for the correct password - and don't want to use the collision mode - (again: this is also mentioned on the --help section and in several forum threads).
The reason why you did crack something with -m 9700 and that 5 character long mask is that all of the other 9 hashes have a corresponding plain text password of exactly 5 letters. This is a very, very rare case and you were very lucky to crack some hashes with -m 9700.
BTW: don't forget that with -m 9710 you "just" found the RC4 "hash", this can be enough for you to "open" the file, but to find a corresponding password you need to do all steps (e.g. continue with -m 9720).
The reason why you did crack something with -m 9700 and that 5 character long mask is that all of the other 9 hashes have a corresponding plain text password of exactly 5 letters. This is a very, very rare case and you were very lucky to crack some hashes with -m 9700.
BTW: don't forget that with -m 9710 you "just" found the RC4 "hash", this can be enough for you to "open" the file, but to find a corresponding password you need to do all steps (e.g. continue with -m 9720).