I have the consumer (home) version. I got it at my local CVS pharmacy, on sale for $89. I believe that the main difference between the two meters is that the physician version will monitor more things (e.g., it will measure LDL directly, while I use a calculated number from the home version) and the physician version costs a lot more.

Wow! That is a big swing. I can understand your concern about low cholesterol. I know it can result in low serotonin levels, although yours might not be low enough for that. Have you noticed any marked mood swings or depression?

One thing I have discovered is that total cholesterol, LDL, and to a lesser extent triglycerides can vary greatly from week to week. (It takes HDL much longer to change.) Sometimes I have trouble believing that a measurement could have changed so much in one week and I will repeat it an hour or so later. I've always found the repeat measurement to be within 10% of the original measurement.

For example, here are my total cholesterol measurements each week since January 1, 2008:

339 (1/1/08)
297
241
243
220
216 (2/4/08)
195
295
193
227 (3/2/08)
262
276
199
205
187 (4/6/08)
238
192
213
239 (5/4/08)
202
230
223
257 (6/1/08)
232
287 (I repeated this one because I had trouble believing it. The second measurement, taken an hour later, was 295, which is well within expected precision.)

These numbers make me think that tests taken ever year or so at the doctor's office are something of a crap shoot. If, for example, your cholesterol has dropped or raised 30 points from one year to the next, it could just mean that's the luck of the draw based on the day that the test was run.