Out of the Silent Planet
I think it's not unusual for Steve to have demos/ideas from previous albums sessions. He is full of ideas.I'd say they weren't even started with, as in proper recording. Maiden was on tight budget at VXI sessions. The X Factor took years, the band had inactive years 1994 and 1997 with the sales and audiences being less than they used to be. VXI had to be released pretty swiftly, maybe also due to the Q4 of 1998 being filled with big metal festivals in South America. They had no B-sides which points to shortened studio time. From that angle it's easy to see how 4 songs could've been left completely undeveloped.
However it's 1998 and Harris has a studio of his own where Maiden recorded 4 albums. So there might be studio demos of the stuff with Blaze. Not songs in preproduction or production just studio demos because Harris has access and knows how to use one.
Maybe they wrote 12-14 songs during VXI sessions (like during TXF sessions), but decided that they will do an 8-songs album again and Steve saved these 4 songs for the next album (i.e. BNW). Besides, Janick wrote only one song for the album, so it's not surprising that Steve has written so many songs. And they already (sort of) had filled the spots in the album with these type of songs - Blood Brothers/CEA (slow song), The Mercenary/Futureal (fast rocker), DOM/The Clansman (song with acoustic parts), The Nomad/DLTTEOAS (song with long instrumental section).
Edit: ''We actually ended up doing 14 songs for TXF album and we used 11'', said Steve, ''which is very unusual for us''.