"So why would i not pour another 100,000 shares into it if i was...

"So why would i not pour another 100,000 shares into it if i was the get a 25% (Maybe reduced by earlier payment) return? "

The NTA per share will be diluted, and the share price will be under pressure. Shareholders in other locations that can't participate in the DRP and who receive cash payments will have their holding diluted unless they add.