I can race across the US and a week later outsprint the British track team but as soon as the duration goes up at decent power the legs aren't responding.
You have been blessed with a bigger engine than most of us though and perhaps the duration and bursty nature of ID weren't enough to grind you into ultra paste. I've PBd a 10mi after TCR but I've also blown spectacularly doing a 50mi after TABR. Generally I wouldn't bother with TTs after ultras.
Big numbers for how long?
I can race across the US and a week later outsprint the British track team but as soon as the duration goes up at decent power the legs aren't responding.