For anybody who's searching for info on these methods, here's what I have concluded (not independently confirmed):
The primary rates request returns elements called
<GuaranteedDaysToDelivery> and <ScheduledDeliveryTime>
The additional Transit Time request by Greg McClellan returns
<EstimatedArrival>/<BusinessTransitDays> and <EstimatedArrival>/<Time>
With the former, the name ("guaranteed") implies a certain degree of certitude; however, we get no values for UPS Ground (but we do for all the rest).
With the latter, the name ("estimated") implies less certitude, but is more realistic. If it's only going to take 1 day to get a package via Ground, this method says so (if the "guaranteed" method returned a value, it would probably be higher than 1, which is less useful). We get values for UPS Ground; however, we occasionally do not get values for 3 Day Select and/or 2nd Day Air. I have concluded that the latter happens when it is not appropriate, i.e. when Ground would get the packages there just as soon. This is a useful way (that did not exist in the HTML UPS module) to screen out methods that are not in the customer's or shipper's interest.
Using the latter method, if you want to add the estimated delivery time, you'll need to add
$transitTime[$serviceDesc]["time"] = $serviceSummary[$s]->getValueByPath("EstimatedArrival/Time");
to the _transitparseResult function, and then do something with it in the quote() function. I added these lines in place of the line that uses $this->servicesTimeintransit[$type]["date"]:
if ($this->servicesTimeintransit[$type]["days"] > 0) {
$_type .= ' (';
$_type .= $this->servicesTimeintransit[$type]["days"] . " business day";
if ($this->servicesTimeintransit[$type]["days"] > 1) $_type .= "s";
if ($this->servicesTimeintransit[$type]["time"]) {
$_type .= ' by ' . efi_convert_ups_time($this->servicesTimeintransit[$type]["time"]);
}
$_type .= ')';
}
(efi_convert_ups() is just a little function to convert the UPS times to a better format)
And if you wanted to get fancy, you could add a marker indicating whether or not the estimated transit time is guaranteed or not, using
if ($transitTime[$serviceDesc]["guaranteed"] == 'Y')