Ok, I'm seeing it now. The page listing all the hotels in the area has "from $X" by each one. When you pick one, the next page shows the first night rate, which may be a lot higher, and "the rate for this room changes on [date] to $Y per night." This only shows the FIRST change, it may not be the only change, and it may not be to the lowest rate. It is only by picking a room type and rate that you see all the rates for all nights (and taxes and fees, but that's a different rant).
In two specific examples, for the Labor Day weekend, Sept. 5-9, for the Lexington and Courtyard Midtown East, the FIRST rate change is on the 2d night, while the CHEAPEST rate is the 3d of 4 nights. But the Lexington shows "from $129" while the AVERAGE for 4 nights is about $215, for the Courtyard "from $189," average $281.
Part of the reason I didn't see this before is that the lowest rate is, of course, for the cheapest room, which is often a queen bed (sometimes a double IIRC) and I look for kings. My bad, I know.
And, to be fair, I would have to say that I think looking for the lowest "from $X" in general does tend to lead to lower overall, or average rates, although not always, and this is just from recollection, not tested in any way.
Having said that, IMHO this still makes the "from $X" info almost useless, as in many cases I still end up looking at 8 or 10 hotels in part of mid-town Manhattan to see which one is cheapest, although admittedly this is better than 15 or 20 I guess. But what would be the most helpful would be to have the website present me with the AVERAGE or TOTAL cost for each hotel for the dates I have entered.
Also, although I don't have an example of this right now, I have seen a different rate for a specific date based upon whether I say I'm staying for 3 nights or 4. In other words, in my example, the rate for Sept. 7 may be different if I say I want Sept. 5-8 or Sept. 5-9. I have no idea whether this is normal, or why it should be the case, but in some instances I have found two separate reservations to be cheaper than one longer one.
It's Marriott's website, and they can do what they want. I won't go far as to call it fraud as some have, but it's less than transparent and/or really helpful.
I'm sure those of you with better brains than mine (which is probably most of you) will enlighten me on the error of my ways. Thanks in advance.