More variance analysis

Yes, of course - that is why they are in the notes!!

but the technical article in acca for material mix and yield variances said "While the calculation of a mix variance can also be done for sales, this is not covered by the Paper F5 syllabus at present.Therefore, I shall concentrate purely on the materials variance here." and it was last updated on 25th feb 2015 ie. not too long ago. so have they made some sort of mistake here in updating the article?

I suggest you look at the F5 syllabus yourself. Try looking at Section C6 of the Study Guide attached to the syllabus. We only have in our lectures and lecture notes topics that are examinable as I have told you before. Have you not looked at your Revision Kit? I don't know which publisher you are using, but the current BPP Revision Kit has 7 questions on sales mix and quantity variances (and some of them are past exam questions!). (I have just emailed my contact at the ACCA to tell them of their error)

Thank you john. i just checked the syllabus and yes you are right indeed, the topic is appearing in the syllabus. It looks like Acca overlooked this comment in the article but in this part of sales mix variance, i don't get the logic behind the formula used for calculating the "sales mix variance" as illustrated in the example in OT course notes.

We are comparing the actual mix (costed at standard profit) with the standard mix for the actual total quantity (costed at standard profit).