Change TimeMachine quota on NAS

I use a Synology NAS as my TimeMachine backup disk. I want to increase the quota of allocated space on the NAS to allow more space to be used by TimeMachine. I know how to increase the quota on the NAS, I have read that when changing the quota that TimeMachine recognizes the increase in size, but does not **use** the increased size. This article was a couple of years old (2012) and I am wondering.

1. Is this still true for 10.8.5?

2. If it is still true, how do I get TimeMachine to recognize and use the newly available space?

Thanks,

Andy