Hi,
Please review SAP Note 1012874 - FAQ extractors 0FI_AP_* 0FI_AR_* 0FI_GL_*(except 10). Question 3 deals with issues like you described.
If you need further assistence, please mention which DataSource you are using, explain in further detail the mismatch, describe your data flow and how the first InfoPrvider looks like (e.g. DSO, key fields), and any other information which might be relevant.
Best regards,
Sander