Custom package with dpkg-deb, apt-get purge deletes folder

[michael@estone.ca]

Hello,
Sorry this isn't exactly related to the AMD64 arch, but I thought
I would quickly ask here before trying debian-user.

I created a custom .deb package with dpkg-deb -b mikesapp.
All my files and such (including the DEBIAN folder) live in mikesapp.
Running dpkg-deb -b creates my .deb file and all is good.
I install with dpkg -i mikesapp.deb.

The program runs and works all good.
I can apt-get remove package, and everything is still happy and clean.
The main problem I have is when I apt-get --purge remove the package.
The --purge wants to delete all the parent directories from the  
installed files.
For example:

Lets say the custom package .deb will install files into
/usr/local/bin/mikesapp

When I apt-get remove the package, the mikesapp folder and its  
contents are deleted. If I apt-get --purge remove the package, it  
removes mikesapp, plus tries to delete bin and local.
bin gets wiped since nothing else was in there, but local stays and  
apt-get replies saying "not empty, so not removed".

Is this normal when building custom .deb packages via dpkg-deb?
Am I missing something when building the package?

Thanks-you,

Mike