PowerShell & Google Maps Time Zone API: Check and Change Computer Time using Internet Time

I've been using WinPE to install images on new PC's and found that since Dell computers come from Texas, the Time Zone and PC clock time needs to be updated to my Time Zone. I'm probably over complicating this process but thought I'd share this anyway:

#Google's time variable is based on the start date/time of 1/1/1970, universal time zone
$startdatetime = [datetime]"1/1/1970 00:00:00Z"

#getting local time and converting to universal time zone
$currentdatetime = (get-date).touniversaltime()

#Google time variable takes the 1/1/1970 date and wants the total seconds from that date to current time
[int]$totalseconds = ($currentdatetime - $startdatetime).totalseconds

#get a server key by signing up for the Google Maps Time Zone API 
#read more here
#note: location just has to be somewhere in your area/time zone
$timezone = invoke-restmethod ("https://maps.googleapis.com/maps/api/timezone/json?location=46,-122" + "&Timestamp=" + $totalseconds + "&key=")
$timezonename = $timezone.timezonename

#since I live in Washington, I have the two possible time zones. Obviously you'll want to add/change time zones based on your location(s).
if ($timezonename -eq "Pacific Daylight Time"){$TZDiff = -7}
if ($timezonename -eq "Pacific Standard Time"){$TZDiff = -8}

#Now I'm pulling local timezone information
$tz = ([timezoneinfo]::local).id
write-host "Local Timezone setting: $tz"

#creating a variable in case the timezone is incorrect
#The ref'd timezone.ps1 script is from Peter Henchley's blog
$changetime = "e:\scripts\timezone.ps1 $timezonename"
if ($tz -ne $timezonename){powershell -executionpolicy bypass $changetime;write-host "Changed Timezone" -f yellow}

#Once the time zone has been adjusted, now we check for time
#We pull current time from www.timeapi.org, convert it to universal time, and add our time zone difference so it equals our current time zone
$webtime = (([datetime](iwr http://www.timeapi.org/utc/now -usebasicparsing).content).touniversaltime()).addhours($TZDiff)
$localhour = (get-date).hour
if ($localhour -ne $webtime.hour){set-date $webtime;write-host "Changed Local Time" -f yellow}

An example of a Google Map Time Zone API reply

dstOffset    : 3600
rawOffset    : -28800
status       : OK
timeZoneId   : America/Los_Angeles
timeZoneName : Pacific Daylight Time

Let me know if you know of a better method of checking for time zones and time without using local computers or domain servers.