That is some SERIOUS movement! Wow. Diva floors for sure!

Here are somethings that might make this more difficult than anticipated (by homeowner and hardwood flooring professional alike):

1. Exotic hardwoods are often VERY hard (as in they chew up and/or kill machines that try to work on them...like sanding machines)

2. Exotics are often very oily; which can make staining a bit of a chore

3. Factory finished floors like the one's in the photo often have aluminum oxide finishes = very difficult to remove during sanding (your photos do NOT show the 'normal' look of AO....but it is entirely possible it is there).

It is possible a highly trained professional hardwood flooring refinisher can deal with this. It is also possible you won't find anyone who will even try. It really is "luck of the draw" when it comes to FINDING the high-end (ahem...expensive) flooring professional. And then it is another luck of the draw if said professional has the ability/tools/time to deal with this floor.

If we assume the WORST case scenario (all three issues listed above are present) here's how it will play out:

1. You will find the very expensive professional who has dealt with this before and has SUCCESSFULLY stained/refinished an exotic like this. They will probably cost MORE than $5/sf for a REGULAR sand/refinish (like white oak).

2. Said professional will come in and realize you have aluminum oxide on the floor. That means an 'up charge' of $2/sf (going rate) to sand off AO finish. This also takes a day or two longer to accomplish (hence the up charge)

3. The exotic is deemed to be SUPER hard = another $2/sf up charge for all the extra machine work needed (hard exotics chew up sanding discs like they are Smarties). Again another day is added to the event.

4. The exotic in question is super oily making staining a MUCH more difficult event...but the professional gets it done to your satisfaction (the floor now looks 'painted') and because of the oiliness the polyurethane has to be chosen with care. Again you are looking at another $1-$2 up charge.

If you are lucky, and everything works out, the Pro will only charge you the $2 up charge for sanding/removing the AO finish and not the other up charge for dealing with a super hard exotic.

If we look at the math, $5/sf + $2/sf + $2/sf = $9/sf.

It would be cheaper to paint the floor black and save up for another floor. Or it would be FASTER to remove the floor ($2/sf to remove) and then replace with $7/sf factory finished hardwood ($3/sf for install) = $12/sf.

And there is something no one has discussed: the gapping between the planks. The floor has shrunk during the winter...which tells me the humidity in the home is not being maintained...and that tells me the HVAC system does NOT have the capacity to ADD humidity during the winter time.

If you want a new hardwood floor in this home (which would be my recommendation) you will also need to UPDATE (ie. spend more money) on the home humidity control. That is an expense most people do not look at when looking at hardwood floors.

In the end, I'm only speculating on how difficult this wood is going to be (and speculating on expense) to refinish. You won't know the ACTUAL cost until someone comes in and tells you their costs.