Found some buggy code that dynamically produced this statement

Insert into COSTTYPE
(ID,COSTTYPE,ALLOWDELTA,ALLOWDELTA)
Values
(1,'TEST','Y','N')

My tests show that the latter of the two is the value actually used. is
this always the case? Shouldn't this produce some sort of error?

Forgive me in advance if this topic has been covered.

Regards,
Mitchell Peek