1923 SC 575 Precancel 3 Bar

I got this precancelled 1923 stamp model SC 575 with Schermack perforations. The fact is that 3 bars can be seen in the precancellation, what could be the reason for this?




*** Moved by Staff to a more appropriate forum. ***

If I understand vending coil production and large-scale local precancel printing correctly, then
Press sheet of 400 stamps, 20x20
Precancel plate of 100 positions, 10x10
This requires 4 imprints of the precancel plate per press sheet, which the vending coil manufacturers wanted intact, rather than the typical precancel user being satisfied with the standard retail panes of 100.

For your stamp, the black arrow denotes the cut-line along the top of your stamp and which ran across the center of the 400-subject press sheet. The primary precancel on your stamp would be from the top row of the 100-position precancel plate and the extra third bar at the top of your stamp would be from the very bottom of the same plate applied too low on the pane above it producing a partial double-print on your stamp. Note also the slight horizontal misalignment of the pair of red and green added bars of the two precancel plate impressions, which further demonstrate being from two different printing cycles. While not common, I do not see any premium for it, other than as a curiosity


As a tangent, here is a fun shift with a different Scott# and precancel type:

Thanks for your answer!!! This is a beautiful community with very good, wise and generous people who are crazy about stamps!!! I am very happy to know my stamps better, thank you all!!