Authors' headline is the general (Box-Cox) form, whose functional form is not rejected while double-log (lambda=0) and linear (lambda=1) are rejected; SR own-price elasticity SE_p = -0.3261 comes from this preferred general form || 'Based on the results of the general form, the short-run own-price elasticity is only -0.3261' (p.1254) and abstract '(1) the double-log and linear forms can be rejected at the 0.05 and 0.01 levels, respectively' (p.1251)
Chang, H. S., and Y. Hsing (1991): “The Demand for Residential Electricity: New Evidence on Time-Varying Elasticities.” Applied Economics 23(7), 1251-1256