I'd argue that this would never be done by hand anyway. The average user will not understand the encoding, and I doubt many will think "Hmm, I have this plus co

I'd argue that this would never be done by hand anyway. The average user will not understand the encoding, and I doubt many will think "Hmm, I have this plus code, but I'd like to only have 1/20th of the precision." Programmatic truncation would still be very easy, as it would just require a new checksum to be calculated post-truncation.