We know that Page Publications did their best to present their reprints in an orderly fashion - consecutively numbered issues reprinting three U.S issues in order between their covers, and in some cases numbering their series as per their U.S counterparts. But sometimes things got out of whack and a bit of mopping up was required.
For example, Chamber of Chills #4:
Given the pattern established in the preceding three issues this would be expected to contain reprints of Chamber of Chills #'s 10, 11 and 12. It does indeed begin with the covers and contents of Chamber of Chills #'s 10 and 11 - front cover honours to #10, and a black and white reprint of #11 on the inside rear cover - and the fact that the short stories contained herein are published in a different order to the U.S issues is but a trifling.
However, instead of continuing with a reprint of Chamber of Chills #12, this issue ties things up by reprinting two stories which missed the cut in previous issues: Jerry's New Job was dropped from Chamber of Chills #3, and Haunt and Run! is missing from Chamber of Chills #2.
Murray and Yaffa would often need to come up with creative ways of accommodating the restrictions of their page count, say by reducing the size of the page or removing a splash page, printing pages sideways, or printing on the inside and back covers. I suppose the short stories in these issues removed the pressure of tampering with the artwork so they could offer complete stories which accorded with their page count.