Undesired auto sort when adding two multiindexes
idx0 = 

timestamp                                          sequence  attribute
2014-11-12 17:02:23.635000-06:00  0                price  
                                                                             count  
                                                                             quantity 

idx1 = 

timestamp                                          sequence  attribute
2014-11-12 17:02:24.060000-06:00  1                price  
                                                                             count  
                                                                             quantity 

idx0 + idx1 = 

timestamp                                sequence  attribute
2014-11-12 23:02:23.635000  0                count  
                                                                   price  
                                                                   quantity 
2014-11-12 23:02:24.060000  1                count  
                                                                   price  
                                                                   quantity 

Any way to solve this?
