So what is the deal for lap infants now on awards to Canada?

If I try to book an award ticket for 1 adult + 1 lap infant on United.com from YVR to SFO, it wants to charge me $20 for the infant's fare + some $44 in taxes.

But if I add the infant on to a Basic Econ rev ticket, there is no lap infant fare (i.e. $0 fare) and taxes are $18 or so (I think because some taxes aren't charged on free tickets).

The webpage linked to above by WineCountryUA now says the following for flights between the U.S., Canada, Mexico & the U.S. Virgin Islands: "Ticket needed, but you only pay applicable taxes or 10% of the adult fare, plus applicable taxes (check fare rules)."

So if I book the adult first and then call in, will I be able to add the lap infant for free or will they try to charge me what United.com is charging - the $20 fare + $44 in taxes? Flight is UA metal.