The two tests are measuring totally different functions of your Breathing/Lung functions. The Oximeter is measuring how much Oxygen is circulating in your blood and I would say this is the most important of the two. To walk that far and not get breathless and not have levels that drop below 97% are completely normal and as they should be.
The other test where you are blowing is measuring how strong you are at, well........blowing lol......as far as I know. So measures how much air you can blow out in one forceful blow. The figures quoted by Toci I am sure will be very accurate. I don't know too much about FEV results.
I have Non-Specific Interstitial Pneumonitis so it is the Oxygen levels in the blood or Oximeter results which are more important for my condition. I check these levels regularly as I am on Oxygen and just want to make sure I am on the correct flow rates for each activity.
To me it would appear that your levels are almost normal. You could do some deep breathing exercises to increase your ability to expel air when you blow forcefully. These levels can be increased sometime depending on what your underlying condition it.
I think this information is accurate but I am not sure so I hope someone else will come along and put me right if I am wrong.
Keep Smiling or in my case Keep Twinkling.
Hugs and Love to you all from
Twinkling Star Xxx