Brihat Parashara Hora Shastra
एकभे तु बहुष्वेको हरेत्स्वांशां बली ग्रहः । नाऽत्र क्षीणस्य चन्द्रस्य पापत्वं मुनिभिः स्मृतम् ॥ ११॥
Benefics in such cases lose only half of what malefics lose. Should there be more than one Grah in a Bhava, the deduction, due to the strongest, will only prevail and not deductions, due to other Grahas in that particular Bhava. Waning Candr is a benefic for this purpose.
english translation
ekabhe tu bahuSveko haretsvAMzAM balI grahaH । nA'tra kSINasya candrasya pApatvaM munibhiH smRtam ॥ 11॥
hk transliteration by Sanscript