Time entry form


Hello, we have a sheet for our trades to track their time. We have one user who can't enter time in half hour increments when filling out the form. He seems to be the only one with this issue, everyone else can enter in 0.5 increments. We have it set as a text/number for the column type and display as a single line text box and the validation as number only, but the guys are able to manually type in if they need to put in time that is say 5.5 or 0.5.