Can't help you with specific bomsec info, however, I can tell you that I have had similar experiences with pestpac.
I spoke with them about it...
The gist of the response was, all orders are subject to asx rules and I guess these rules are written in to the software.
My experiences are orders go manual;
if you have changed price's or volume more than once (same stock),
have a cross trade (trying to buy with a sell order in or vice versa),
trading on the same stock within 10? minutes (a warning of 'you have placed similar order/s recently),
and also for no apparent reason...
a small order was one ie $minimum orders, also large orders over 20k$
I have found if I delay hitting the final trigger button by 10 seconds (because I am reading the warnings of course...) the order I expect to go manual often goes straight to market, and I suspect a 'timed out' scenario occurs letting it 'straight through' to market, but not always.
Pestpac will trade on chi, despite asx volume's indicating that the trade could happen immediately via their platform.
Trades often don't even show in the course of trading list as they only show asx trades.
They also said that they are working on showing chi data also, but I suspect that will never come to fruition, unless they show it separately, which I would accept and prefer.
From a programming perspective, it would be highly complicated to migrate data into one screen.
I have sometimes wondered if they trade on chi knowing full well that they can buy on chi possibly lower than my order price, and then onsell to me at my order price!
Do you trust them when not everything they do is easy to validate?
This all adds up to using the data shown is often pointless, as they do want they want by trading on chi.
I guess what I would like to see, is the asx rules that apply and are built into their software.
F.Rock