Statutory Language: Must We Do Shall?

I've been going through the new statutes which have been passed by the General Assembly so that I can brief our local law enforcement on them and present them at at local CLE (when you are in deepest darkest Far Southwest Virginia you do your own CLE's or you drive 6-10 hours east to get your hours). I've noticed some stylistic trends which which the General Assembly has become obsessed with. In particular, every time the General Assembly amends or alters a statute whatever gnomes are in charge of typing the new statute up are going through the statutes and changing any place a number is written out to plain numbers (ie. 35 instead of thirty five).   Apparently the accepted wisdom has changed from a written number being preferable to the numerical symbol being preferable.  Who knows why the accepted wisdom changed? I figure that some senior statute writing gnome has a reason, but the reality is that someone probably preferred numbers and came up with an excuse. It doesn't matter to me either way; both work and if it makes life more satisfying to the statute writing gnomes the General Assembly keeps working in the dungeons of the capital building, more power to them. In fact, I've been impressed by the patience which has been shown. They've not attempted to change all the statutes at once, they've been satisfied with making the stylistic changes as the opportunity presented itself.

Of course, there's always the exception which proves the rule . . .

§ 54.1-4005. Sale of goods pawned.\
No pawnbroker shall sell any pawn or pledge item until (i) it has been in his possession for the minimum term set forth in the memorandum, but not less than thirty 30 days, plus a grace period of fifteen 15 days and (ii) a statement of ownership is obtained from the pawner. If a motor vehicle is pawned, the owner of the motor vehicle shall comply with the requirements of § 46.2-637. In the event of default by the pawner, the pawnbroker must shall comply with the requirements of § 46.2-633. Otherwise, the pawnbroker must shall comply with the requirements of § 46.2-636 et seq. All sales of items pursuant to this section may be made by the pawnbroker in the ordinary course of his business.

I read that over three times, sure that there had to be a meaningful change in the statute somewhere. Nope. It's purely stylistic preference. I assumed the number change was just because the opportunity presented itself. This left the must / shall change. My definition of both is "non-discretionary requirement to do."  To be sure, I checked and Merriam Webster online listed each as a synonym of the other.

I can see someone looking at this and thinking "Must seems more passive mandate. Let's use an active mandate like shall."  That might even be a good idea EXCEPT that the Virginia appellate courts have quite often interpreted "shall" as "should."  I don't think that line of reasoning should apply here, but the fact that it exists at all makes the decision to change "must" into "shall" less of a good choice than it might have seemed.