"Monitor" does not monitor for RNQ0103 (target for numeric operation is too small)?

I put a Monitor in my code to specifically catch this error, but it
doesn't seem to work. Here is the code. Note the TruncNbr(*no) that I
put in the H-spec to make sure that was working (but I think that is the
default, right?)
I didn't see anything in the archives.

H OPTION (*NoDebugIO : *SrcStmt) TruncNbr(*no)
.
.
D MinutesLate S 5p 0
.
.
monitor;
MinutesLate = %diff(%timestamp : LateTS : *minutes);
on-error;
MinutesLate = 99999;
endMON;

Yesterday I added a check specifically for the RNQ0103 in hopes that it
would catch the error, but I don't think I should have to do that. I
don't know if that fixed it, but I haven't gotten any complaints about
getting the error since then!

monitor;
MinutesLate = %diff(%timestamp : LateTS : *minutes);
on-error 0103; // Target too small to hold result
MinutesLate = 99999;
on-error;
MinutesLate = 99999;
endMON;

Mr. Kerry Lockwood
Celadon Trucking, Inc.
9503 E. 33rd Street
Indianapolis, IN 46235
(317) 972-7000 ext. 2147


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