If I understand your first case correctly, the HBD rewards may have also been accounted from the all time rewards in their HP value and that may lead for the discrepancy. So if I have 9k in my all time rewards, we can assume that half of that comes from the HBD rewards that was shown in HP value. Then the interest will eventually reduce the KE over time but wasn't the interest also the curation reward and was already accounted for all time rewards (author reward + curation reward)?

I also did monitor if the same amount of hive was added to my HP and from the stats shown on Hivebuzz and it seems to be adding the same amount.

My theory is that previously, both HP rewards and HBD on its HP value are included as All time rewards then change at some point to only account for HP rewards due to an update to the code but wasn't able to do the same with the previous data then just combine those rewards altogether and that what makes the discrepancy.

For the second case, It may be plausible if an account set an alt account as beneficiary but as much as I know for the 2 accounts above, only shawn has a beneficiary set on his post and that was from using inleo frontend that automatically sets 5% of his reward for beneficiary and posting on some communities will also set them with a certain % of the reward post. And given that 2 unrelated accounts has such a great discrepancy between their held HP and curation rewards, it may not be the cause for that.

I also think we need to look a bit further then only KE ratio for instance if the extracted value is used for growing SPL is that then considered as extracting (not everything is as black and white).

I agree to this as the hive was not really taken out of the blockchain but used to helps to support SPL and/or other hive Dapps and helps grow the blockchains apps which in turn grows the chain as a whole which benefits everyone.