Hi
In the trigger log at the moment of checking the conditions selection name Public Service is shown as third favourite with a lay price of 7.0. This meets the condition where third favourites lay price is equal or less than matching_number which is 7.
For info ranking in MFP is defined by selections back price so the lowest back price is the Favourite.
You can sort selections by lay price (or any other variable) and then address by an index. Please see the helpfile for explanations of these conditions. The second condition will check third fav by lay price against matching_number:
selections sorting order is defined by lay_price
and selections trigger expression match_3_lay_price is equal or less than matching_number
btw US racing markets have very wide spreads between back and lay prices and much lower matched volume so you can expect wild fluctuations in prices and ranks
its a learning curve and you are doing well