Be careful with normalizing against USD values. At the time both ventures started the ratio was more like 1BTC@10USD. Thus an Avalon unit had the equivalent cost of 130 BTC, or about 2600 USD now.

Thus: 50 / 460 BTC / share =  0.11 BTC / share

Also, the cost for the increase in mining operations by the proposed factor 6 is included in the share price. So you're looking at up to 300 MH/s / share, which bumps the equivalent price to about 0.5 - 0.8 BTC / share.

I'd say 0.2 BTC / share is a bargain. 0.3 BTC / share is a good price.

But please do your own price discovery

Interestingly, with the Avalon-2 unit priced at $1500 and the BTC price shooting up to $20, the Avalon-2 unit has an equivalent BTC price of 75 BTC. What we see here is deflation at its finest: When looking at it from the BTC perspective, prices for hashpower decreased significantly. This means an Avalon-1 unit has to "make up" for a 55 BTC LOSS against the Avalon-2 unit.