I have a quilt I made using 800-fill down that seems to have noticeably lost loft over four years of gentle, careful use. The same observation applies to an 800-fill down jacket that I made.

Could it be construction tecniqes? Of all the things that I've made,(although they work o.k.), they seem to lack the quality of most manufactued goods. Even the cheap stuff.If I had more $$ I would buy all my gear. Even from other DIYers. Then I could blame them for defects.
Enjoy your next trip...