Question about Find and Replace function

[Stgoldberg at aol.com]

I've used Revolution to create an invoice program consisting of a Main stack 
and several substacks in which all the stacks   contain "2006" as the last 
word of their names.   Now, for 2007, I want to change all the times "2006" 
appears in the stack names and scripts to "2007".   I've done this successfully but 
have some questions I don't understand about the process:

a. I opened "Find and Replace..." from the Edit menu", typed in "2006 in the 
"Find" field and checked off "Name" and "Script", since these are the places 
where "2006" appears. While in the Main stack, I chose the search process to 
occur in "This stack file and its stack files", then clicked "Find", which came 
up with some "337 objects found"
b.   I then typed in "2007" into the "Replace with" field, clicked on 
"Replace in All"
c. Interestingly, the program found and replaced "2006" a number of times but 
not all of them.   I had to repeat the process about 6 times in order to 
replace all the instances of "2006".   My questions are as follows:

A.   What is the "Find" program doing that requires 6 passes through the 
entire procedure to get all the words?
B. What is the difference between selecting "This stack file" versus "This 
stack" and "This stack file and its stack files"?   I presume that "This stack 
file and its stack files" refers to this stack and its substacks.   What is the 
difference between a stack file and a stack?
"Find and Replace" seems to be doing its job, but I'd just like to   
understand the process a little better.   Thanks.
Steve Goldberg