Though Variable spreads snowball limits and protective stops inadvertently and if the gap between Bid and Ask reach a stop or limit level, this may cause a conditional order. The trader is faced with an extra variable to be considered. This does not happen with fixed variables as there is synchronization between Bid and Ask. Fixed spreads are steady allowing the trader to be aware of levels and parameters giving way to specified money management and strategic planning to better the situation. Take a look at:
http://www.ismarkets.com for more information and guidance.