In addition to mnemonics with the same number of digits you entered,
we also provide mnemonics with one extra digit at the end, for a couple of reasons.
First, they still work from some phones (mostly land lines): if you were to dial the extra digit at the end you
would still be connected to the right number. Second, some phone numbers have very few mnemonic possibilities,
and allowing a random final digit can open up a lot more options
and you can always tell people to ignore the last letter/digit.
We have separated out the extra digit memonics from the exact ones for your convenience, so you can easily decide whether to take advantage of them.