That might have gone down for a whole host of reasons but it usually decreases when the owner appeals the value based on condition, a recent sale or appraisal, etc.

First, always aim for clear and regular communication.

No, most hosts in the United States avoid them at all costs, due to the lack of host friendliness.

We host a local meetup and our team of investor agents operates in this market. 

It's just a matter of finding them.Other options would be finding a full service co-host and negotiating something with them to take a smaller commission (or salary) to just handle that part of it. 

When a PMS is used the host becomes the merchant of record for all other sites, so it's our responsibility to make sure payment has been made.   

Does it happen regularly and no one catches it, sure.

Scott from Bigger Pockets speaks there regularly. 

Then a regular 1031 exchange can be done with no problem.

I don't enjoy nurturing and closing sellers on a regular basis.