You might find part of the conversation Kyronix had with folks on TC earlier of interest ...I've not gone Rambo yet because we haven't seen the tier 5 rewards. I've been on TC all day working on them, don't know if I will make it to tier 5 though this weekend.
<5487074>Uqest: Hi kyronix is the mempo with 1fc imbuable? or is it a brand new pre set artifact?
Kyronix: it's imbuable
<5487074>Uqest: is it possible to get it with only 1 tir item crates ? or you absolutly need 5 tier items crates ?
Mylar Tyrmitore: Yeah, funny how things work
Kyronix: the mempo?
Kyronix: the teir just amps up the values for rewards that come in quantity
<5487074>Uqest: ok so the mempo from Slim is just matter of luck to get it ?
Kyronix: yup, gotta roll those dice
<5487074>Uqest: so the tier doesnt amps itschance to get it actually
Kyronix: just for resource and gold rewards
I'm reading that as meaning the chances of the deco and 'special' items are equally low whatever you turn in - which makes sense of some folks getting the trade signs. for example, on their first or second completed trade quest - whilst the quantities of materials (and gold deposited to the town?) rise with the tier of the deal you complete....but it's VERY late and far too warm here so I may be completely wrong