They did target 2-2.5xNTA for pre-IPO and the double for IPO I think.
With just short of 32 million shares for the pre-IPO and IPO, the goal of 400MUSD gives an AVERAGE of 12.5$ per share.
If we assume the same number of shares for the IPO as the pre-IPO, i.e 16 million shares each, and 2.5xNTA for pre-IPO and 5xNTA for IPO that means an NTA of 3.67$.
Your 7.5$ equals 2xNTA, i.e we need more for the IPO itself (however, at the time of the IPO our NTA should be higher and thus a lower xNTA is required).
However, Dan also said that the interest was strong and that they didn't want to oversell - i.e maybe we'll get more than 2.5xNTA in pre-IPO and/or sell less in pre-IPO and more in IPO?