Interesting problem with collision

I fixed it with some help from a program called rockout.bmx that came with blitzmax. I put the following code in the attacking missiles update method and it worked like a charm. Life is good. Do you think I found a bug based on the source code listed above?

For Local City:Cities = EachIn CitiesLst

Local ox:Int = x - width / 2
Local oy:Int = y - height / 2

Local ogx:Int = City.x - City.width / 2
Local ogy:Int = City.y - City.width / 2

' Check collision...

If OverLap (ox, oy, ox + width, oy + height, ogx, ogy, ogx + City.width, ogy + City.height)
AddExplosion(City.x, City.y, 1)
PlaySound nukeSnd
City.target = 0
AttackingMissileLst.remove(Self)
End If
Next