Disagree with Tan Teng Boo's stock valuation method

In his latest newsletter dated 22 Aug 2014, he named some stocks that are deemed bubbles floating around the KLSE.

The stocks are A&M, BOILERM, COASTAL, ECOWLD, GDEX, HLCAP, IJACOBS, INARI, MUH, MYEG, N2N, NARRA, PELIKAN, PTARAS, SBCCORP, SCGM, and SMRT.

I have great respect for him. However, I quite disagree with the valuation method he adopted in his article. Look at some examples:

A&M
"It has a market capitalisation of over RM500m. For its financial year ended 31 Dec 2013, A&M Realty recorded sales of only RM145m and net earnings of only RM32m. If a PE ratio of 10 times is applied, the market capitalisation of A&M should be RM320."

BOILERM
"It has a market capitalisation of over RM861m. For its financial year ended 31 Mar 2014, Boilermech recorded sales of RM242m and net earnings of over RM31. If a PE ratio of 10 times is applied, the market capitalisation of Boilermech should be RM310m. Wow!"

SBCCORP
"It has a market capitalisation of over RM336m. For its financial year ended 31 Mar 2014, SBC recorded sales of RM139m and net earnings of over RM33m. Can such a high profit margin be sustained and for how long?"

Is stock valuation as straight forward as merely looking at PE multiple? What about other aspects such as assets, cash flow and future prospects? I also disagree that the justification is based on historical earnings and not future earnings.

Was A&M's 60% stake in 2,000 acres of land in Pulau Carey taken into consideration? Assuming RM10psf, the 60% stake alone is sufficient to cover its market cap. Besides being profitable, it is in net cash position (RM95m at group level as at 31 March 2014), and have long list of assets in the group.

For Boilerm, does he consider the growth potential of the group? Boilerm is acquiring another piece of land for expansion. Does a company with growth potential not warrant higher PE multiple? And maybe premium attached to it given the name of the major shareholder in the company? Besides, Boilerm has very strong cash position.

I believe the potential of Sbccorp lies in the upcoming development of Jesselton Quay in Kota Kinabalu, which is also a factor why TTB likes Suria, the Sabah port operator that has 18% share of GDV in the development. It has GDV of RM1.8b and expected PBT margin of 20%. Even so, I think the GDV and profit margin could have been understated. Besides, Sbccorp has other developments and assets in the group. With an estimated RNAV of RM6.60.share (CIMB) and a combined GDV of RM6.2b to be developed over 10 years, is there bubble in the stock?

While I think Boilerm is not cheap and Sbccorp is fairly valued at the moment, I am inclined to think A&M still has some upside potential when the development at Pulau Carey commences.