DO NOT rely on Estibot for valuation purposes. Or rather, any purpose.
I sold a co.uk once for a couple of thousand that it estimated at 0. More recently I sold a name for $1300 that it also estimated at 0. I submitted those names so I could have a good laugh.
Estibot is a complete and utter waste of time. If you're using it for metrics, there are better tools out there for those too.
The problem with Estibot is that it's a backwards looking tool. Looking at past performance. And so if you get a $0 valuation, you have to understand why that valuation is zero. Oftentimes this is because the domain is newly registered. I'm not saying this was the case in your example. But oftentimes that could be the reason.
Also the comparable sales data, is often wacky and irrelevant. This is because, there is not enough data for the domain you are trying to evaluate.
I think we all have to understand how difficult it is to get an "accurate" valuation. It's impossible. Largely because the buyer behavior on 1 domain, might not be exactly the same on a similar domain. As long as you interpret the valuations understanding an imponderable number of variables. You should be OK.
I think, like every other valuation tool, Estibot has it's quirks. No tool is a panacea for providing accurate valuations. It's impossible. But if you use your own thoughts on top of the backbone provided by Estibot, I think you can get to the $1-2k valuations, just fine.
Lighten up and use some of your own research of why you bought those domains in the first place. Estibot, being a bot, doesn't have access to the information inside your own head. Which is adding the forward looking element, which a bot doesn't have access too.
It's also possible that 99% of those $0 valuations are actually accurate. So it isn't really possible to state positively, that Estibot's valuations are useless, based on a sample of 2.
I think Estibot is much maligned, but still a useful tool. If you understand it's shortcomings and modify it's valuations with your own forward looking research. I will continue to use it.