Because once the config gets loaded the 2nd script that gets loaded last and it overwrites the 1st one. That is why only one works. You might try merging the two scripts together to see what will happen, but I'm not sure if it will work.
You can try this: bind mouse1 "+vstr attackOn attackOff" set attackOn "+attack; +sprint; vstr fov1" set attackOff "-attack; -attack; -sprint; -sprint; vstr fov2" set fov1 "set cg_fov 90" set fov2 "set cg_fov 115"
Not sure if it will work, since I'm writing this from memory and haven't used a scripts since 2007.