question about calling SP with parameter

Suppose I have a SP with parameter, say it as below:

mysp @p1 = v1, @p2 = v2, @p3 = v3

In PB(11.5) I can this SP by a datawindow.

It's working fine. Then I want to add one more parameter to this SP like:

mysp @p1 = v1, @p2 = v2, @p3 = v3, @p4 = null

for @p4, the default is null.

I made the change in PB, but not change the SP in database(Sybase ASE 12)

then I run the pb app, it's working fine! No error.

So it means I can change the SP at anytime for this case???