This is true. After the Great Disappointment, William Miller admitted his mistake regarding Christ’s returning on October 22, 1844, and he also gave up believing that October 22 had any prophetic significance. On the other hand, Ellen White never discarded her belief in the prophetic significance of the October 22 date, so she had no reason to admit a mistake had been made regarding SDASBC 3.4
the calculation, beyond the obvious fact that Christ had not returned that day. Several references showing her consistent position are given below. SDASBC 4.1