Sorry to bug you with this again, but IMHO your customers are interested in a bit more specific time frame.
Why? Well, you can find some threads about the produced file sizes. As well as the time the OCR process takes.
These as well as other points are addressed by the new Abby Engine release:
http://www.abbyy.de/adx/aspx/adxGetMedia.aspx?DocID=71755760-360c-4780-be4e-adc374c665ac
BTW: version 8 of the engine is out of support.
Kind regards,
Carsten