C Constants Aren’t Automatically Promoted

Quick, what’s wrong with this code snippet…

#define MAX_INTERVAL	(60*1000)

unsigned long int LoggedTime;
unsigned long int NowTime;

byte LogNeeded;

... snippage ...

LogNeeded = (NowTime >= (LoggedTime + MAX_INTERVAL)); 

Yeah, that constant up there should look like this:

#define MAX_INTERVAL (60*1000ul)

Took me a while to figure that out. Again.