After re-partitioning the drive to make the extended partition, did you reboot? Unfortunately, sometimes, Linux cannot re-read the partition table and so mkfs uses the previous-known size of the partition to size the filesystem. You'll need to reboot.

Alternatively, you can tell mke2fs how big a filesystem to make with something like:
The $[ ... ] expression calculates how many 4k-blocks you need to fill 230 mega-blocks.

Keep in mind, 230 Megablocks is about 210 Gigabytes (GB), not 230. You can expect 12% less than that, so about 202 GB will be free after creation.

You can get better utilization with some tweaks. Since this is going to be for your VMs, you can use a smaller ratio of inodes-blocks. Also, sparse_super should be default, but just in case....