Yeah...I saw that also and I'm going to give them a mea culpa since the rules are an introduction to AS.
You can easily solve this...buy more 'Mechs :D
I have a few to choose from - creating a database, extracted the MUL for my collection and AS Clan Invasion cards. Missing movement data from the Alpha Strike Force Builder is a pain , the tonnage to SZ was easy enough, would be great if they added MV, Mvj , Role and SZ. Then I wouldn't have to copy and paste into a spreadsheet the MUL data (filtered for availability) and look up the weights and role from a similarly captured AS force build data.
The intent was to use it to generate lances and stars from my collection(80 mechs) and the AS cards I have for about 200 mechs in my AS spread sheet and don't fancy entering the movement from the cards or the pdf generated from the builder.