According to the survey, Macs were cheaper to troubleshoot and required fewer help desk calls; system configuration, user training, and servers/networks/printing were all cheaper for a Mac environment than a PC environment. Software licensing fees turned out to be nearly identical for both platforms.
The survey doesn't factor in the costs of the Macs themselves; Macs do present a large up-front investment, especially compared to the budget-priced Dells you usually see populating most office cubicles. However, half of the survey respondents noted they switched to a Mac platform because of a lower total cost of ownership.
The up-front cost is still a turn-off to many IT admins, though, some of whom clearly haven't even bothered shopping around for a Mac because of the perceived expense: "You can buy a PC for $400, while the cheapest Mac is over a thousand," one admin noted. Apparently someone's never heard of the Mac mini, which ranges from $599 for the cheapest model up to $999 for the server-class Mini. Even the cheapest Mac mini would be a more than capable replacement for a $400 Dell or HP computer.
After having worked in a PC-only office environment, I'm not surprised at all that Macs turn out to be cheaper to manage than PCs. The Dell workstations we used at my last job in the US crapped out on us all the time, and software issues cost us hours of lost productivity every week. Between Windows XP, Office 2000, IE 6, and Lotus Notes, our IT admins were kept very busy, especially since almost none of the rank-and-file office workers had the confidence to troubleshoot even the most basic Windows errors themselves. This was at a very large media corporation, too, one that easily could have afforded better hardware and software if they hadn't been so entrenched in the "Macs are too expensive" mindset.
Apple doesn't tend to go out of its way to target Macs to the enterprise, preferring instead to focus on everyday consumers. Even so, it looks like IT admins, frustrated with the support issues and high maintenance costs of PCs, are at least starting to consider the Mac as a viable alternate platform.