I can see many potentials not bother with the process.I am slowly pushing some tenants into email communications and invoicing.

A Validation Notice is a invoice of the total amount in which you owe, total amount of interest,and to whom you owe and which collection service you are being collected from.

They just sent me very vague invoices that say "flooring $5000," "appliances $5000" etc...

I'll spare you that math, but TLDR is to be honest with the IRS about your income, and if you've got one-time rehab expenses then keep all receipts/invoices. 

Today they send us an edited quick books invoice marked as paid and said no discounts are given for work not done in bulk.

The time you spent on it is zero and you just deduct the cost of the cleaning from the deposit since you have proof of invoice with a description of the neglect they discover and clean.

They charged 10% fee of the total sub invoice.  2.

* Are all my invoices uploaded to my owner portal?

When you focus so much on working on the accounting side you tend to sacrifice your investment side.I want to have a better understanding how investors like you and I, how much volume of invoices, cutting checks, balancing the books, reconcile the bank accounts, credit card, applying receipts, and the likes do you ask yourself that you need to hire someone?

For example:The PM should upload all invoices and documents to the owners portal but the owners portal has nothing in it, and he only sends a monthly statement by e mail.