The SSIA structure is such that on encashment any growth is subject to "exit tax". So if you encash it now that it is in profit, the Life Assurance company is obliged to deduct 40% of the growth. Even if you do not encash the policy now but leave it for some years, the Life company is obliged to deduct any "exit tax" on each 8 year anniversary. When the first 8 year anniversary arose (2010?) it probably was in negative value and thus no "exit tax" liability arose. The next 8 year anniversary will presumably be circa 2016, so if you leave it invested until then (and assuming it is still in profit at that stage), the "exit tax" will be deducted from the value whether you encash or not.
Hope this helps.