Hi
The market_score has been fairly reliable recently but sometimes feeds can fail or as the previous poster mentioned there could be a mistake etc. If you are going to use market_score for betting you should be aware of the disclaimer on the Betfair website and in MFP manual.
Betfair - bottom of website page:
"Warning: Although the current score, time elapsed, video and other data provided on this site is sourced from "live" feeds provided by third parties, you should be aware that this data may be subject to a time delay and/or be inaccurate. Please also be aware that other Betfair customers may have access to data that is faster and/or more accurate than the data shown on the Betfair site. If you rely on this data to place bets, you do so entirely at your own risk. Betfair provides this data AS IS with no warranty as to the accuracy, completeness or timeliness of such data and accepts no responsibility for any loss (direct or indirect) suffered by you as a result of your reliance on it."