Telling a partial truth is also deceptive. Between your friend finding out you asked Dan rather than Dan asking you and finding out you asked Dan because you felt they were inept, they are more likely to be upset over the latter. If they're gonna find out, they're gonna find out, and telling the truth won't abate that. The difference between the lie and truth here is that with the truth they're more likely to want to dig deeper given that you always work together. Granted, they could wonder why you accepted Dan's proposal, but it's not as odd as if you had initiated.