From the rule book
Positions 5th to 8th in the Final Meeting Classification will be according to the results from the Semi Finals (Race 21 & 22). The 2 Riders who finish 3rd in each of the Semi Finals will be 5th and 6th in the Final Meeting Classification, with the higher ranked rider from Intermediate Classification 5th and the lower ranked rider 6th. This rule will FIM Speedway Grand Prix World Championship 29 apply if both riders complete, or fail to complete the Semi Final. If only one of these riders fail to complete the Semi Final for any reason, he will be placed 6th in the final meeting classification. The 2 Riders who finish 4th in each of the Semi Finals will be 7th and 8th in the Final Meeting Classification, with the higher ranked rider from Intermediate Classification 7th and the lower ranked rider 8th. This rule will apply if both riders complete, or fail to complete the Semi Final. If only one of these riders fail to complete the Semi Final for any reason, he will be placed 8th in the final meeting classification.