future movement, page-98

The section you are referring to in the Pooled Development Funds Act regarding the 30% requirement is as copied below. The section refers to the investment not exceeding 30% of the total "immediately after it is made". As such I don't believe any significant increase in the value of any single investment of the PDF which pushes its value over 30% of the PDF's total value would fall foul of the legislation, nor as you mention require a re-balancing of the book.

25 PDF not to commit more than 30% of its committed capital to investee company
(1) Unless the Board otherwise approves, the investment must be such that, immediately after it is made, the total of:
(a) all amounts paid on the shares in the investee company held by the PDF; and
(b) all amounts remaining unpaid on those shares; and
(ba) all amounts the PDF has paid to acquire options in the investee company that the PDF has not yet exercised; and
(bb) all amounts the PDF has lent to the investee company that remain outstanding;does not exceed 30% of the total of:
(c) the shareholders’ funds of the PDF; and
(d) all amounts remaining unpaid on the issued shares in the PDF.