Are the standards the same in Canada as in the US?
The more stringent requirements in the US went into effect in September 2005.
I interpret that to mean that all cars sold since then meet the same standards. So if one manufacturer says 48, they all should meet that requirement.
Other people interpret that to mean that although all cars meet the same minimum requirements, some manufacturers might go above and beyond and test their anchors to a higher level. (So in other words, maybe Honda really does mean it when they say 40 lbs.)
Personally, I believe that all anchors are rated to the 48-lb standard. Vehicle manufacturers tend to put child safety on the back burner, and I can't imagine any of them voluntarily testing their anchors to a higher level, especially if they're not going to use it as a marketing ploy. I also suspect that anchors tend to come from the same manufacturer, though I have no way of confirming that.
But, putting that aside, you must stop using LATCH in a Honda at 40 lbs, because that's Honda's official stance. On the other hand, if you call Honda and ask them, you'll probably get 25 different answers. So take your pick.