if its a 5 man squad then it SHOULD cost 300mp because each grenadier entity is currently worth 60mp in stats.
you cant just add an extra entity and also slash the price on the squad without reducing some stats on the grendier entity.
also 5 man gren squad won't fix their issues. Their teching costs need to be adjusted and some or the underwhelming units need a bit of a buff (222, sniper etc.)
