Add Artillery VT Proximity Fuze

Add the revolutionary VT proximity fuze to US anti-aircraft (AA), air defense (AD), and artillery (ATY) to close another startling hole in original PG/AG and Pacific General (PACG).

The US secret weapon used miniature radar in a shell to tell it when to explode and OSRD's Vannevar Bush estimated that the VT improved US 5" AA effectiveness by 5x. The VT greatly increased the effectiveness of both AA/AD against aircraft (including kamikazes and V-1 buzz bombs) and artillery against ground targets.
Add the VT to US AA/AD/artillery in PG/AG/PACG by significantly increasing Soft Attack (SA) and adjust costs accordingly.

Existing ship/gun units can upgrade to VT ammunition in the same way that AT gun and tank destroyer units can upgrade to HVAP/APCR/APDS ammunition.

See also:

Add radios for artillery command-control-communications

Artillery's Initiative, HEAT ammunition, and anti-tank (AT) Hard Attack (HA)