Direct SAP table update issues

Hello Experts,

    Currently, in my customer system i see one custom program which is updating SAP standard table (SCM EWM) directly using below statement.

  "update /SAPAPO/MATLWH set rsqty = zmax_qty where matid = mat_wa_chunk-matid and scuguid = mat_wa_chunk-entitled_id."

    I see that program is there in production from last almost 2 years and that is a product quantity update program which has to run periodically.

    As per my knowledge, this is not at all acceptable. Can you please share me your thoughts, what kind of problems will occur and pre-defined

    errors with direct data base table update?

    What should we do now on this?

    Thank you in advance.