I believe the 92 Explosif was made of Concept, but on the 93 frames only the seat tube and the stays were Concept. If they used a Concept sticker, this may have been only to satisfy a requirement under US consumer-protection law that any sticker must refer to the part that it's fixed to - in this case, the seat tube.
I've seen two different descriptions of the top and down tubes on the 93 Explosif - one that they were both Tange Prestige Ultimate Ultralight (which confusingly isn't as light as Superlight!), and the other that the down tube was externally fluted, implying that it was Tange Prestige Ultimate Ultrastrong (which the 94 Explosif definitely used). Either way, Ultimate was a higher-end tubeset than Concept, so it might make sense to use an Ultimate sticker.
May I ask you guys if you have fluted downtubes, or is that getting a bit personal?
I've seen two different descriptions of the top and down tubes on the 93 Explosif - one that they were both Tange Prestige Ultimate Ultralight (which confusingly isn't as light as Superlight!), and the other that the down tube was externally fluted, implying that it was Tange Prestige Ultimate Ultrastrong (which the 94 Explosif definitely used). Either way, Ultimate was a higher-end tubeset than Concept, so it might make sense to use an Ultimate sticker.
May I ask you guys if you have fluted downtubes, or is that getting a bit personal?