Mori V'Rabi doesn't know

 

In Shulchan Aruch (Y.D. 283) it says One may not write a מגילה with only a few פרשיות of the Torah. When writing a Chumash one must write a complete Torah with all the (פרשיות - (חמשה חומשי תורה.  The ט"ז writes, that being it is too expensive to write a complete  Torah for children learning Chumash, therefore, Poskim were lenient and allowed to write a מגילה with just a few פרשיות. The היתר is based on the Pasuk עת לעשות לה' הפרו תורתך. There are times when we don't follow the Halacha for a greater benefit. So that children will be able to learn we allow writing only a few פרשיות. and there is no need to write a complete חומש Mori V’Rabi Harav Hagaon R. Shlomo Miller Shlita said he doesn't know if a Segulah ( for accumulating wealth)  would be enough of a reason for "הפרו תורתך" Mori V'Rabi doesn't know of a היתר for a Sofer to write a פרשת קטרת on a קלף