The 14.5 volt 4.2 aH Lithium Ion battery came out after the catalog and documentation was prepared. It appears that the electronics for many of the new battery operated Festool products now adjust for the supply voltage of battery.
Many of the 14.5v and 18v tools that shipped with the 3.0 aH battery are now shipping with the 4.2 aH version.
Lithium Ion batteries now come with built-in electronics to limit voltage and amperage draws to prevent over heating and burnout or flaming.
It certainly does not hurt to ask.