uid's are the order of objects or the number of object that is created, for example, you got 100 different objects created then you destroy them , the next object will have the uid 101 and not 1 ...
for the object order to recycle you need to use IID which is the order spawned for each object of same type...
while uid is the order of any object, all objects created no matter the type of them.
if that doesnt cut it, you can make a localvariable on tile objects, and for each tile seed assign the count based on a loop.
ex : for each tile slot add to variableid 1+loopindex if you want to start the counting from 1 and not from 0.