why the different peaks by HINT-ATAC all under the zero line and motif Activity Score are negativate

Question

[zhao03]

Hi, i used HINT-ATAC to find motif of S3 and S5 sample, and then, i used rgt-hint differential to discover the different motif between S3 and S5, however, the result figure shows all the motif Activity Score are negativate. how can i understand? thank you