InterContinental Hotels: Priority Club & Inter-Continental Ambassador - Different rates from different sites?

Has anyone else noticed rate differences between the PC web site and the Intercon site?

Today I found that the Intercon site was between $5 and $100+ per night less expensive than the same room (and same dates) on the PC site. This struck me as really odd and I'm not sure if it is some computer glitch or if it's a regular thing.

I was looking at the IC Melbourne on the 29th of this month.

Yes different rates from different sites. Also different advanced purchase rates with/without corporate rate. And different options on the Ambassador site. And different rates as the arrival date approaches. A bit of a moving target...

Is this unique to IC?

Or can you similar find better rates at an Holiday Inn site for HI compared to the PC site, or at an HI Express site for HIX compared to the PC site, or at a StayBridge site for SB compared to the PC site?

(So far, I've only ever bothered to check the PC site, and when I don't like the rate I either use points or just move to another hotel family. I didn't realize that the brand's own site could possibly be lower than the PC site!)

And the "non smoking room" preference will eliminate the option for the lowest price room and the option for award nights at some hotels.

Yes different rates from different sites. Also different advanced purchase rates with/without corporate rate. And different options on the Ambassador site. And different rates as the arrival date approaches. A bit of a moving target...

Oh I see, a challenge, I love a good challenge! :p

Today I found that the Intercon site was between $5 and $100+ per night less expensive than the same room (and same dates) on the PC site.
It could be a glitch. I consistently get IC rates much higher in my search results, but everything is correct after I select the hotel of choice.

Yes different rates from different sites. Also different advanced purchase rates with/without corporate rate. And different options on the Ambassador site. And different rates as the arrival date approaches.
...and minimum stay requirements in some ICs (e.g. London, San Francisco).