By linking the number of man-hours to the expected turnover of each individual account as regards both sales managers and project managers, ...

A man-hour is the amount of work performed by an average worker in one hour. It is used in written "estimates" for estimation of the total amount of uninterrupted labour required to perform a task. For example, researching and writing a college paper might require twenty man-hours. Preparing a family banquet from scratch might require ten man-hours.

The advantage of the man-hour concept is that it can be used to estimate the impact of staff changes on the amount of time required for a task. This is done by dividing the number of man-hours by the number of workers available.

http://en.wikipedia.org/wiki/Man-hour

Als je per account weet hoeveel uur een verkoopmanager of een projectmanager naar verwachting daaraan zal besteden, kun je uitrekenen hoeveel verkoopmanagers of projectmanagers je nodig hebt

Mijn veronderstelling is dat men op basis van de verwachte omzet heeft uitgerekend hoeveel "bestedingsuren" daarmee gemoeid zijn

Ik denk dat "man-hours" in deze context een aannemelijke optie is

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Note added at 5 hrs (2010-02-06 21:16:02 GMT)
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This is perhaps better, just:

"By linking man-hours"

Probably they refer to the concept of man-hours

"Door bestedingsuren te koppelen aan de verwachte omzet" might mean "by calculating the number of man-hours on the basis of the expected turnover"