The Federal Home Loan Bank of Boston, continuing to struggle to return to profitability, has decided to cut expenses by at least 5 percent, or $3 million, by eliminating 18 staff positions. The personnel cuts are a part of a larger plan the Boston Bank is instituting to help bring itself back into the black after losing $105 million in the third quarter of 2009, on top of $4 million in... the second quarter and $83 million in the first.