Citing the hardware manual for clarity:
"HORIZONTAL BEAM POSITION
The horizontal beam position has a value of $0 to $E2. The least signifieant bit is not used in the comparison, so there are 113 positions available for Copper operations. This corresponds to 4 pixels in low resolution and 8 pixels in high resolution. Horizontal blanking falls in the range of $0F to $35. The standard screen (320 pixels wide) has an
unused horizontal portion of $04 to $47 (during which only the background color is displayed).
All lines are not the same length in NTSC. Every other line is a long line (228 color clocks, 0-$E3), with the others being 227 color clocks long. In PAL, they are all 227 long. The display sees all these lines as 227 1/2 color clocks long, while the copper sees alternating long & short lines.
Just to make sure I understood it correctly:
There are 227 positions (e.g.color clocks)in the beam counter because eventhough E2 corresponds to 226 the 00 possition also counts, correct? If so, then why, there are 113 possitions for the Copper? Shouldn't there be 114? (the least significant bit doesn't count, halving the value, but position 00 should still count no?
Also in the last paragraph: "The display sees all these lines as 227 1/2 color clocks long, while the copper sees alternating long & short lines." To what are they refering whith "display", the beam counter?