For this particular file it will work just as well using the 'LTP' 99.999% of the time
But if you use any other rules files in the future which trigger on selections by order of favouritism you may then have to move it to the default 'back price' to get them to trigger correctly.
Obviously at some point in the past you've changed this from the default 'back price' to something else but then forgot about it and that's what's caused this rules file not to trigger correctly the last few days so its just something to bear in mind for the future