The start is just the origin of sequencing, which is not necessarily the origin of replication. You can see quite nicely in Ensembl Bacteria, which uses EMBL-Bank genome and annotation files directly, without processing to find the origin of replication.

Here's a genome where the origin of sequencing is the origin of replication. The origin of sequencing is shown at the top, as a red arrow. The obvious GC and gene skew on either side of ther chromosome clearly show demonstrate the positions of the origin and terminus of replication.

Here's a genome where it's not. The origin of sequencing is, again, at the top. But the GC skew seems to be ~60º away from vertical, suggesting that the origin and terminus are at the 4 o'clock and 10 o'clock position (no idea which is which).

Here's a genome where there's no way of knowing. No GC or gene skew, so the origin of replication could be anywhere.