The multiple millisecond difference between sts and jop is highly variable and seems to be a factor of busyness at the exchange. As the CME now offers the ability to have order numbers published on market data messages I thought that it might be interesting to see if sts - jop were different for market data and it would be particularly interesting to see if market data representing a filled order were available before that same data became available to the submitter of the order (if not and if not regularly, then the submitter of the order would know before the public and would be in possession for some (small) period time of non public information - whether or not such information were material would be a matter for others to decide, but if it were held to be material then any action taken before the public knew of the filled order info could be considered insider trading). With just a few inspections I found that most of the time the public is informed about the filled orders before the order submitters are informed - but I did not look at large enough sample to draw a strong conclusion.
Trading Technologies will allow you to monitor exchange latency in real time when we release a new metric for the TT platform in late May. The Audit Trail in TT already exposes hedge latency numbers for Autospreader hedge orders. This is an internal latency where we show the difference between the time TT receives the fill on a quote order to the time TT releases the hedge order. The metric we will introduce next month will expose exchange latency where users will see the difference between the time TT submits an order and the time the exchange acknowledges the order.