The interesting thing about Gawain is that he seems instrumental both in Ywain's fall and also his redemption. His philosophy, that love is nurtured well by worthiness (chilvaric deeds) and moderate consumption (getting a break once in a while), though at first the cause of Ywain losing Alundyne's trust, ultimately proves to be true. Immediately after recovering from his madness, Ywain sets out to do chilvaric deeds, going on the "knight-automatic" where he left off with Gawain, as if, at least subconsciously, he was still taking his advice to heart. Yet, it is noteworthy that the whole redemption quest is structured almost like a competition with Gawain: wherever Gawain was requested, Ywain arrives in his stead to the job, until they compete directly in the knightly duel. Though Ywain holds no ill will to Gawain, in some sense this competition and the subsequent confrontation would be fully warranted even if they recognized each other: if Alundyne was deceived by Ywain, then surely Ywain was deceived by Gawain.
This parallelism in mind, it seems very likely that what Gawain said was essentially true but required some correction. Gawain's words are confirmed as the correct doctrine in the eyes of love, but it seems, in the moment, he was using them with an ulterior motive: to gain back his friend, creating strife between love and chilvarly, where instead should be balance (the coupling between Venus and Mars being important for the later Ovidian tradition). That Gawain possibly had a more superficial idea of chilvary in mind (comradery, perhaps merrymaking?) could be argued by the subtle contrast between the two chilvaring periods. With Gawain, they go to tournaments and participate in other courtly activities, but what Ywain does alone could easily translate as good deeds in God's creation (itself a fusion of military deeds and deeds of love, but this might be too far, the focus in markedly on ladies in distress)