I checked the
SRD, & re-read the
Natural Weapons section, the
Full Attack portion, & other relevant passages of the
combat rules, & I don't see anything that says monsters can't have up to 4 attacks. In fact, the full attack RAW seem to indicate that only 2 attacks is a strange exception, not the rule. If you can find the proper wording that clarifies this matter, please let me know. I'd prefer to be as true to monster creation guidelines as possible, of course. Until then, I'll just keep doing it wrong (or right, or whatever
).