I have noticed that my mobile mt5 (assume is accurate?) and 24option can be out by quite a bit sometimes up to 5 pips. worryingly I found this on their website:
24OPTION.COM WOULD LIKE TO REITERATE THAT THE PRICE FEEDS CONTAINED WITHIN THIS WEBSITE WERE PROVIDED BY MARKET MAKERS FOR CONVENIENCE ONLY AND AS SUCH THE PRICES MAY NOT REFLECT ACTUAL OR CURRENT MARKET PRICES.
Just jumping in here but my research shows brokers are operating with algorithms working down to nano seconds to determine market place lead (volume in the trade etc.). Variables like weather, platform (fibre, microwave) all need to be considered. I am aware that some traders have enough margin to alter the balance on short term trades. Hope your research works out.