I have a couple of ads that are performing well. Screenshot of one of them below:

I tried creating some variations of the ad but none of them performed well. The CTR was similar to the above ad but the CPM cost was too high. Even duplicating the ad gave a 4x high cost. Screenshot of duplicate ad below:

I can't figure out what I am doing wrong. Even ads with a better CTR than the first ad have oCPM price around $30.
This is my first time running newsfeed ads. The first three ads I created are performing well with oCPM around $7 but all new ads that I tried over the past three days have oCPM above $20 even though some had a better CTR than my original ads. I tried bidding CPC for newsfeed but didn't get any traffic.
Is there some way to replicate this ad's performance?
With oCPM, not really.
One of the issues here is that you are launching them at different times of day and different days of the week wherein the level of competition and resulting news feed CPM will differ.
The established ads will have a slightly different audience (i.e. user base reached), at the mercy of the oCPM system, so won't perform identically to the new ones.
Your best bet is to launch the new ads and let them run a few days (if still converting well!) and see how their performance changes with time cf. the original ads.
As far as I know, there is no shortcut here when using the oCPM system, you simply have to base your decisions on more than a day of data.
For what it's worth, I have also had ads jump up to $30 CPM but then drop to $10 the next day, rising up to say $15 in the evenings.
Simple Solution : Keep it running !
looks like I should be ready to lose a couple hundred dollars each time I create a new oCPM ad 
Just budget the new ads to $10 a day and see what they do - that way you will build up and understanding of how the CPM for that demo varies without flushing away money.
I had this happen to me a while back. Started a new campaign and got 11 cent clicks in a demo/targeting situation where I was usually getting over .30 . I tried duplicating, increasing budget, but it didn't matter. The click costs where always 3 or 4x.
I left the original campaign running and eventually it climbed to .30 or so as well.
oCPM is just really weird and glitchy in my experience. I have had situations where I started off ridiculously cheap with clicks and also situations where for some reason I had CPM costs approaching $30. I've tried to find a rhyme or reason to it but I can't. Seems like shit just happens and it's part of the game.