The Bohemians’ 25% bonus to spears decreases the number of strikes required to take down a unit of the same age by 1.
For example, spears vs bloodlines/armor-less scouts would take 2 hits after the bonus, pikes against bloodlines light cav would take 3 hits, and pikes against bloodlines knights would take 4 hits.
Pikes against Mongol bloodlines hussars would take 3 hits, while pikes against bloodlines cavalier would take 5 hits.
FU Halbs against bloodlines Hussars, if they miss the last cavalry armor or are late in taking it, would take 2 hits after the bonus.
However, FU Halbs against bloodlines paladin and heavy camel would still take 4 hits.
If a non-Bohemian pike is facing a cavalier, the number of hits required to take them down would be 7 instead of the usual 6.
In this case, it might be better to just obtain the blast furnace technology for your pikes instead of halbs, since halbs would not have an effect on the time-to-kill unless there is another unit shooting the hussars.
This does not apply to Mongol Hussars.