Comparing the rules for searchlights between the TacOps:Advanced Rules (Corrected 4th Printing) and BattleMech Manual (Corrected 4th Printing), they appear to directly contradict each other.
On p.62 of the BMM, under Dusk/Dawn, it states that there is no to-hit penalty when the target is illuminated by a searchlight.
On p.56 of TacOps:AR under Dusk/Dawn, it states that searchlights do not offset the to-hit penalties.
On p.62 of the BMM, under Full Moon Night and Moonless Night, it states that 'mechs with searchlights ignore the MP penalty from the lighting condition (which is detailed).
On p.56 of TacOps:AR, although under Full Moon Night/Glare and Moonless Night/Solar Flare, it states "modify movement and combat as follows", but there is no mention of the movement penalty (although it is listed on the table on p.34). Nowhere is it stated that 'mechs with searchlights can ignore the MP penalty.
(I understood that the BMM rules were the same, but clarified, but in this case, they seem to explicitly contradict each other.)