Get-WMI query has backwards results

OK, I am totally lost on this one.   I have this code:

$call1 = "\\mhapp1\Scripts\Tools\MHRebootTool\RebootUtility.exe"

function Get-Uptime  {

$o = Get-WmiObject -Class win32_operatingsystem

    (Get-Date).date - $o.ConvertToDateTime($o.LastBootUpTime)}

if (($o).TotalDays -gt 7) {&$call1}

Now, what I expect to happen is on any machine that has TotalDays greater than 7 days the &$Call1 should execute.   So I have a workstation that has not rebooted for 48 days.  I run this script and nothing happens.  Yet, when I change the -gt to a -lt then the rebootutility.exe DOES run.  why?

on the machine I'm testing on I ran the above code 'without' the IF statement.  I replaced the IF statement with Get-Uptime.  Here is what Get-Uptime says:

Days              : 48

Hours             : 13

Minutes           : 3

Seconds           : 44

Milliseconds      : 624

Ticks             : 41942246248010

TotalDays         : 48.5442664907523

TotalHours        : 1165.06239577806

TotalMinutes      : 69903.7437466833

TotalSeconds      : 4194224.624801

TotalMilliseconds : 4194224624.801