Only one thing does not understand - where will the platform take the initial data? From an open reporting? And if there are errors, then you will have to check everything first. Do an audit. And if there is an error or data there, then they will remain in this system, on the blockchain?
I would expect errors to remain in both the system and the blockchain and store corrections in new transactions. Just like with software version control systems, you don't erase history (to be clear, it's technically possible, but not recommended) but you append a new commit to fix a past error.
How can this be so? Each block follows from the previous one. If the error is in block 100, and it is fixed in block 200, then all blocks 100 through 199 contain an error. They need to be fixed. If you do this as shown, the blockchain is not needed, it makes no sense.
How can you fix the error in block 100 through 199? Remember the blocks contain the hash of the invoice data. You would need to roll back the blockchain, you'd have to fork, which is a no-no. Blocks are immutable. All you can do is add a new block and say "block 100 through 199 contain an error, here is the fix".
There could be another way if the documents are stored in IPFS and the blocks only contain a pointer to the document. Then you'd be able to change the data in the document without having to change the blockchain. But then you lose the data integrity, which is the whole point of PayPie.
