Although this has been said, it hasn't been explained:
The difference between using a field with a max of 128 and a max of 256 is only one bit, not 4. For those not yet versed in binary, that is to say: for 87654321

bit position	place value
1	1
2	2
3	4
4	8
5	16
6	32
7	64
8	128

Now, shortening it to 7 bits would give you a 1/8 compression at the expense of not allowing any data that uses the 8th bit. I regard this as a mistake, because it can cause all kinds of problems, re: SMTP, AIX /dev/tty*

As an aside, this data set will probably be too short to get a decent compression because of different sorts of overhead. Maybe this is a creative use for freeze/thaw??? (that's from Storable).

Update: 2 Mins later: Ah, I am aware that the OP wanted code reduction, not compression. Well, ignore the last of my ramblings.

mhoward - at - hattmoward.org