Devas: offerings and merit sharing

In Jāṇussoṇi sutta (AN 10.177) the brahmin asks the Buddha whether offers to departed relatives and family members benefit them. The Buddha says that **"on the right occasion, brahmin, it can be of benefit not on a wrong occasion"**, and later on, he says about someone who is reborn in the deva's world that **"this is a wrong occasion, when the gift is not of benefit to one living there"**. At the same time, we find in suttas such as Ratana Sutta and quite a few others, references not only to devas desiring offerings, humans making offerings to them, and even sharing merits with them. Of course, it's a fact known that the many (if not all?) traditions, specially in the Theravada countries support the practice of offerings and merit sharing with devas. My questions then are: a) Does any literature (eg. commentaries) deal with this seemingly conflict? b) Are there any known explanations by elders of any tradition commenting on this sutta?