Hello Rndeleon1988 and welcome to the forum.
Yes, under the same driving conditions it is reasonable to expect similar fuel economy, but there are many factors that can impact this. I wouldn't expect break-in to cause this, but I suppose it could contribute.
The current production Mirage responds very well to careful driving technique, and it is common to see fuel economy numbers in the upper 40s. Here's a few things to look out for - best of all, they cost nothing.
Make sure your tires are properly inflated. For an example, when I bought my Mirage
(See here - Speck) it sat on the lot so long it's tires were low on air. Now, I keep them over-inflated. I, as well as others here, find it improves the ride and handling somewhat. If you do try this, pay attention to the maximum pressure listed on your tire's sidewall.
Also, pay attention to your driving technique, especially a heavy foot on the accelerator. But you probably already knew that.
It's been pointed out here that one thing that is guaranteed to rob fuel economy is the brakes, so leave plenty of room ahead and try to use the brakes sparingly.
The Mirage, like most any car using an internal combustion engine, does best when warmed up. Short trips with cold, thick motor oil takes more fuel to do it's thing. If you are interested, read up on engine block heaters (there goes my 'cost nothing' proposition...) A few owners here use them year-round to improve their fuel economy. I just got one from Amazon and look forward to trying it out.
So there's just a few things to consider - I hope that helps. Take a look at the forum's Fuel Economy Log - found at the top of every page. Many forum members are easily beating the rated numbers. Some others are not that concerned and just drive as they need, enjoying the easy-to-drive, affordable, reliable transportation that the Mirage offers.
There are loads of helpful folks here more than willing to help another owner make the most of their Mirage. Let us know if there's anything else, and I'm sure there will be others who will chime in.