The いとへん (aka 糸部｛べきぶ｝) has two written forms, one written with three dots on the bottom and one written with a 小 on the bottom. In modern Japanese computer fonts (esp. Mincho fonts), the latter form is used. In the K'ang-hsi (康熙) Dictionary (which is the de facto standard for the Japanese 旧字体), the later is treated as the standard writing shape.
The 当用漢字字体表 also uses the latter form as the standard, but meanwhile it also states that, for the いとへん, 「点画の...方向...必ずしも拘束しないものがある」. (see, e.g., the 文化庁's page here).
Therefore, could both written shapes of the いとへん be considered equally correct in handwriting? Which would be more common, in casual and formal handwriting, respectively?