Hi, I'm an Australian physicist currently working in fisheries modelling, which should be a clue to the fact that I love data processing. I'm also highly familiar with AFL (car'n the crows - Adelaide born and bred) and being an Aussie, I'm more likely to be available when you need me.
If you already have the last 10 years of data, this would be straightforward for me to calculate for you. The simplest way to identify if there is a pattern to what you're looking at would be for me to graph the subset of data and any correlations between variables for you, and I could do this easily (given only the bulk data).
I can also show you summaries of the data for the subset of when the number of scoring shots is the same, and perhaps the reason is clearer from that.
If you do not have the data yet, I am skilled at web-scraping, and could obtain these for you, but that would be beyond my bid. I recently completed a scraping project which obtained the last few years of [login to view URL] NFL scores automatically, and that took just 4 hours to write, test, and perform the scraping. This would be an additional $75, but you would gain an offline database of the scores that you can analyse at your own pace. If you would like the program source code for this (which will continue to scrape the scores as the season progresses) that would be an additional $50, but would come with output tables to your specifications and some statistics support.
I hope to hear from you soon. - Jonathan