It seems to me that attacks were based on an "ascending armor class" scheme. To hit value were as per chart, but that chart remained the same at all levels. Each character had a bonus to hit as they progressed in levels.
I put together a copy of this for myself back in 2012 with an original booklets style cover. I took snapshots of the two poorly scanned pages (pages 3 and 4 in your version Zulgyan), lightened them and then stitched them back into the document. Made those pages much more readable. I'd be happy to supply pdfs of those two pages if you'd like to split and merge them into your document.