@Frito Bandito That does sound like it could be low. Did you use the before and after bathroom scale method? You probably eliminated as many of these variables as possible but for reference of the method see below:
Cheap bath scales are notoriously both inaccurate and imprecise especially at the low end of the possible measurements.
Ways to get the best results out of whatever equipment you have include:
-Level surface
-smooth, hard surface
-Doing the test several times in a row
-noting exactly where your feet are placed and your balance, how you hold your bike etc. can help limit the variability.
-knowing that whatever variability you notice in any one measurement is within the error possibilities for each measurement so the final error could be double or more assuming calibrated scale /balance.
-bathroom scales are not calibrated after installation or throwing them in the closet etc. so...
But they are much better than nothing and the inclusion of your body weight at a single point in time puts the scale in a much more accurate range. $20 digital scales are usually pretty accurate for their use case: people whose weight is variable throughout the day due to drinking, eating, burning calories, sweating, using the toilet, etc.