upstream Source patches and patch systems

[John Dong]

Can you clarify these two points? To my 2AM mind it reads as if the  
latter says "Same rules except completely different rules" :)
On Oct 7, 2009, at 1:02 AM, fabrice wrote:

> - if it's a Debian package and no previous modifications has been  
> done,
> modify directly the source, and do not introduce a patch system
> - if it's an Ubuntu (-0ubuntuX) package, the same rule apply, with the
> added rule that adding a patch system is preferred when no upstream
> source modifications has been done previously