The table below gives the results of three titrations carried out with 0.200 M HCl to determine the molarity of a given NaOH solution using phenolphthalein as indicator. NaOH was taken in the burette and HCl was taken in a conical flask for the titrations.

The actual molarity of the prepared NaOH solution was 0.220 $$\text{mol dm}^{-3}$$.
Which among the following could be the reason for the wrong value obtained in titration III?