Hopper items duplicate

Found duplicate items using a hopper.
The scheme of the screenshots may this scheme redundant. The key point - two hoppers must be are attached to each other.
How to play:
1. Assemble the circuit. The more pairs of hoppers - the sooner will be the result.
2. Put one of a pair of hoppers one item (i use hopper, iron and diamond blocks).
3. Achieve unload and load current chunk. F3 + A I did not work, i use the teleportation of a few thousand blocks, waited a few seconds and teleported back. You can run back as far, as well as, I think, to use the portal to hell or to the end.
4. Go back, check the number of things in the hopper.
5. Repeat steps 3 and 4 until things will be duplicated in one of the pairs of hoppers.

I took about 10 teleportation back and forth to achieve the result.

Repeat duplication in the SSP I could not, I only work in SMP. Perhaps this affect the outcome of network latency.

(Append later) Yes, duplication works when unloading / loading chunk. Distance hoppers (perpendicular to the line hoppers) at a distance view-distance + 2 chunks just duplicate items.
Total: at the moment I have 28 pairs of hoppers with status indication (comparator + lamp), as well as train path perpendicular to the length of the hopper view-distance + 2 chunks. About a minute of riding in the trolley (view-distance = 2) gives about 3-5 duplicates.
It is necessary to clarify that view-distance refers server option from file server.properties

ps. Sorry for badly english, i use google translate...