When it comes to concrete roof tiles, you will see two basic profiles, double barrel, and flat. Where double barrel has several variations in terms of dimensions, the flat tiles are just flat. You may find concrete tiles that don’t interlock, but in case, you are using a concrete tile, then it will most likely be of the interlocking variety. These tiles have a water channel on the underside, which can be a weak point in certain profiles of tile. Of the two tiles, i.e., double-barrel tile and flat, the first one is better because of its ability to withstand wear and tear in a much better way than its flatter counterpart.
With flat tiles, the issue of missing corners on the bottom water channel start to appear, which will force people to replace the tiles. These breakages are not the fault of the roofer who installed the roof, but the tiles have a weakness, so if you are planning to have flat concrete tiles installed on your roof, then you should drop that idea and instead have double-barrel concrete tiles installed just because they are so much better. You can sit and discuss the details with a professional roofing company in your area before finalizing anything.