Complex sentence: The Tiger II was developed late in the war and built in relatively small numbers, with 1,500 Tiger IIs being ordered--slightly more than the 1,347 Tiger I tanks produced--but Tiger II production was severely disrupted by Allied bombing.
Split into simpler sentences: The Tiger II was developed late in the war and built in relatively small numbers. Orders were placed for 1,500 Tiger IIs--slightly more than the 1,347 Tiger I tanks produced--but Tiger II production was severely disrupted by Allied bombing.