Use of PEG 3350 + PEG 400 as Base

Respected all,
Can anyone tell me that how efficient is use of PEG 3350 + PEG 400 Base in formulation of combination of Anti-fungal + Cortico-steroid (Especially Fluocinolone Acetonide ) ointment than use of PEG 4000 + PEG 400.
Whether use PEG 3350 + PEG 400 Base enhance the stability of the formulation, if means - How?