Hmmm can you put up a flood light angles toward the whole area? This might be a lighting issue and the best way to determine that is to wash the space with light and then reassess the situation.

‘Angled’

Because when you compare the uppers and lowers in the far interior corners they seem to be a fine match. I think this is just the way the light is hitting the area outside of the kitchen.

I absolutely notice the difference and wonder if it is a lighting issue.

Your crown seems proud of the cabinets and I wonder if that is making a shadow type situation on the uppers. Also, your end panels appear to be in an open space, likely across from windows. They are perhaps getting hit with more light than other cabinets here.

The upper to the right of your sink is getting hit with more light there and it is a lighter looking part of the upper. Another hint that makes me think light.

What does it look like at night? With lights angled towards the cabinets? Daytime but with shades down?

The cabinet maker made for us a door sample with the stain that we have agreed. I compared it with the upper cabinets, the stain looks different (see picture). Do you find that the upper cabinets look more reddish and the door sample more yellowish?

Yes - I think the doors look different. How does the sample door compare to the lowers?

Thank you all for your help.

I just took some pictures at night time.

Picture 1: Potlights turn on

Picture 2 & 3: Potlights turn off. Only 1 white light on.

During the day, I see the color variation more, the upper cabinets look reddish.

Cabinet maker said they used the same ingredients as in the sample door for staining the cabinets and the color variation is due to lighting.