Just trying to think of this logically:
If Arrow sell 10,000 copies of a title, at say £9 a copy unlimited, £12 limited wholesale they'll make £96,000 nett profit. If we factor in a cost for production and licensing of £70,500 (75% of nett profit from 10,000 disc packages [£67,500] with a surplus nett cost of £1.50 per unit for the LE) that leaves a gross profit of £25,500 per title.
If they sold the same amount of purely unlimited stock, there'd be a nett profit of £90,000 with the same base production costs (£67,500) leaving a £22,500 GP per title.
Therefore, theoretically, keeping the Limited Edition titles will actually make more money.