From the info that JB sent through to the fanpage the Spitfire was untended as a companion to the S10. At the time of lanch of the SF gunshops didnt have compressors or offer refills so many S10 owners had several spare bottles and relied on friendly dive centres. When used together a buddy bottle top up with the pressure indicator/bleed valve working correctly gave results embarrassing its peer in the range
It sounds like your Firebird is a typical "transient charge" factory job