Can Someone Explain These Coil Stamp Perforations?

There isn't much information documented on Palestine Mandate coils, and from what little there is - in broad strokes - coil stamps existed in one of two forms: one was by paste-up from guillotined strips and the other was by continuous coil.

The paste-up types don't exhibit any special perforations, they look like regular postage stamps. But the continuous roll types have - every few stamps - one with either a very thick (wide) tooth or one with a very narrow tooth:

This is a 5m strip with a "key stamp" bearing the thick tooth:


This is a 10m strip with a "key stamp" bearing the thin tooth (barely perceptible in the image):


My question is, why would continuous rolls have these types of perforation and what purpose did they serve? Is this phenomenon observed on coil stamps of other countries?

Was it possible if they were using comb perforations on continuously attached stamps to begin the new comb placement either closer to where it previously ended (thin) or farther from where it previously ended (thick)?

Gum-side, it is very hard ( on my computer ) to see what you are talking about. Could you please use black background when scanning stamps?


Peter

My apologies for that - they're not my images. Here are mine, but the difference is, what has been documented so far is a) either a pattern of just a thick perf tooth or a thin perf tooth at the far end of the horizontal axis - not both together, and b) a periodic occurence, once every 3-4 stamps.

My illustrations here show both perf types together and on a constant basis at the far edge of each horizontal axis: a thin tooth for the upper edge of the hole and a thicker tooth at the bottom. Also, the documented pattern belongs to a coil type with 14 horizontal perf holes; the ones in my images here are with 13 holes.





* these images are just for illustration: the purpose of my question in this thread is about these types of perforations in general, not specifically about the illustrations I've posted now;